Most B2B companies hit the same wall: your product is solid, your existing customers are happy, but your pipeline isn't growing fast enough. You can hire SDRs internally (expensive, slow to ramp) or you can work with a lead generation agency that already has the systems, data, and processes dialed in.

The best B2B lead gen agencies don't just send emails. They research your ideal customer profile, build targeted prospect lists, craft personalized outreach, manage multi-channel campaigns, and hand you qualified meetings. You focus on closing deals.

Here are the 7 best B2B lead generation agencies in 2026.

1. OutreachBloom

Best for: B2B companies that want reliable, done-for-you lead generation through cold email

OutreachBloom is a B2B lead generation agency built around cold email outreach. They handle the full pipeline: defining your ICP, building targeted prospect lists from premium B2B data sources, setting up and warming dedicated sending domains, writing personalized email sequences, sending at scale, and managing replies.

What makes OutreachBloom stand out in the lead gen space is their operational focus. Rather than offering a dozen services and spreading thin, they've gone deep on one channel and made it work consistently. They set up fresh domains with DKIM, DMARC, and SPF authentication, warm them properly, and launch campaigns only when deliverability is dialed in.

Their team filters and qualifies replies before forwarding them to you, so you're not sifting through out-of-office messages and "not interested" responses. You get qualified conversations ready for your sales team.

Best for: Startups and growing B2B companies that want consistent meetings without building an internal SDR team Services: ICP definition, lead list building, domain and email infrastructure, copywriting, campaign management, reply qualification Pros: Truly done-for-you, deep deliverability expertise, no long-term lock-in, focused execution Cons: Cold email only (no phone or LinkedIn), requires discovery call for pricing

2. Belkins

Best for: Enterprise companies that need a full-service, multi-channel lead generation partner

Belkins is one of the most established names in B2B lead generation. With over 800 clients served and more than 50,000 email variations tested, they bring serious scale and data to outbound campaigns. They combine cold email, LinkedIn outreach, cold calling, and appointment setting into coordinated campaigns managed by dedicated teams.

Each client gets a team of researchers, copywriters, SDRs, and a project manager. Belkins handles everything from lead research and email deliverability to appointment setting and CRM integration. They also offer a LinkedIn influencer program for executives who want to build personal brand alongside outbound.

Best for: Mid-market and enterprise B2B companies with larger budgets Services: Cold email, LinkedIn outreach, appointment setting, lead research, SDR teams, CRM integration Pricing: $5,000–$15,000/month Pros: Massive scale, proven results, omnichannel campaigns, dedicated teams, strong data Cons: Premium pricing, longer ramp-up time, may be overkill for small teams

3. SalesHive

Best for: Companies that want US-based sales reps with month-to-month flexibility

SalesHive offers B2B lead generation through US-based SDRs backed by their proprietary AI sales platform. They handle cold email, cold calling, and LinkedIn outreach with transparent pricing and month-to-month contracts.

The flexibility angle is their biggest draw. Most lead gen agencies lock you into 3-6 month commitments. SalesHive lets you scale up or down monthly, which is ideal for companies testing outbound for the first time or dealing with seasonal demand. Their AI platform provides real-time campaign analytics and performance tracking.

Best for: Companies wanting to test outbound without long-term commitment Services: Cold email, cold calling, LinkedIn outreach, dedicated US-based SDRs, AI analytics platform Pricing: Starts around $5,000/month Pros: Month-to-month contracts, US-based SDRs, transparent pricing, real-time analytics Cons: Higher cost than offshore options, less email-specific depth than specialized agencies

4. Callbox

Best for: Enterprise B2B companies in tech, healthcare, and professional services

Callbox is a multi-channel B2B lead generation company with over 20 years of experience. They combine cold calling, email, LinkedIn, live chat, and webinars into account-based marketing campaigns. Their Pipeline CRM platform tracks leads through every touchpoint.

Callbox's strength is industry specialization. They have dedicated teams for technology, healthcare, finance, manufacturing, and professional services. This means your campaigns are managed by people who understand your buyers' language, pain points, and decision-making processes.

Best for: Enterprise B2B companies in regulated or complex industries Services: Cold calling, email marketing, LinkedIn, live chat, webinars, ABM, Pipeline CRM Pricing: Custom quotes, typically $5,000–$15,000/month Pros: Deep industry expertise, 20+ year track record, multi-channel ABM, proprietary CRM Cons: Enterprise-focused pricing, longer sales cycle for the agency itself, less agile than smaller firms

5. Cleverly

Best for: B2B companies that want LinkedIn-led lead generation with predictable costs

Cleverly started as a LinkedIn outreach agency and has expanded into cold email and multi-channel campaigns. They've analyzed data from thousands of LinkedIn campaigns, giving them strong pattern recognition for what messaging converts on the platform.

Their pay-per-lead pricing model makes them unique. Instead of paying a flat retainer regardless of results, you can pay based on qualified leads delivered. For companies cautious about agency ROI, this performance-based model reduces risk. Cleverly also offers LinkedIn content creation and advertising services to complement outbound.

Best for: Companies where decision-makers are active on LinkedIn Services: LinkedIn outreach, cold email, pay-per-lead, LinkedIn content creation, LinkedIn advertising Pricing: Pay-per-lead available, retainers from $1,000/month Pros: LinkedIn expertise, pay-per-lead reduces risk, data-driven messaging, accessible pricing Cons: Email is a secondary channel, less deliverability depth, smaller operation than Belkins

6. CIENCE

Best for: Companies that need research-backed outbound with a large SDR team

CIENCE combines human researchers with AI-powered tools to build highly targeted prospect lists and execute multi-channel outbound campaigns. They employ large teams of researchers who manually verify and enrich lead data before outreach begins.

Their GO Data platform provides access to a proprietary B2B contact database, and their SDR teams run email, phone, and LinkedIn campaigns. CIENCE is particularly strong for companies with complex ICPs where off-the-shelf data isn't accurate enough. Their research teams dig deeper than standard data providers.

Best for: Companies with complex, hard-to-target ICPs Services: Lead research, data enrichment, cold email, cold calling, LinkedIn, SDR teams, GO Data platform Pricing: $4,200–$9,000+/month Pros: Deep research capability, proprietary data, large SDR teams, multi-channel Cons: Premium pricing, can be slow to ramp, complex onboarding process

7. LevelUp Leads

Best for: SaaS and tech companies targeting technical buyers

LevelUp Leads is a B2B lead generation agency that specializes in the technology sector. They understand how to reach and engage technical decision-makers like CTOs, VP of Engineering, DevOps leads, and IT directors.

Their process combines ICP research, account-based targeting, cold email, LinkedIn, and phone outreach. What sets them apart is their copywriting for technical audiences. They know that CTOs don't respond to the same messaging as marketing directors. Their outreach is direct, technical, and focused on solving real problems rather than generic sales pitches.

Best for: Tech companies selling to engineering, IT, and technical leadership Services: Cold email, LinkedIn, phone outreach, ICP research, account-based marketing, technical copywriting Pricing: Starts around $3,000/month Pros: Tech sector expertise, understands technical buyers, account-based approach, strong copywriting Cons: Not ideal for non-tech industries, smaller team than enterprise agencies

How to Choose the Right B2B Lead Gen Agency

Start with your situation:

Tight budget, want email-only? OutreachBloom delivers focused, fully managed cold email without the overhead of multi-channel.
Need omnichannel at scale? Belkins or Callbox bring dedicated teams across email, phone, LinkedIn, and more.
Want flexibility? SalesHive's month-to-month contracts let you test without commitment.
LinkedIn is where your buyers live? Cleverly has the deepest LinkedIn data and offers pay-per-lead pricing.
Complex ICP? CIENCE's research teams build custom prospect lists that off-the-shelf data can't match.
Selling to technical buyers? LevelUp Leads writes outreach that resonates with CTOs and engineers.

Questions to ask before signing:

What's your process for defining and refining our ICP? Good agencies iterate on targeting based on campaign data.
How do you source and verify lead data? Bad data means wasted campaigns. Ask about data providers and verification processes.
What does a qualified lead mean to you? Define this upfront. A "lead" should mean a qualified meeting, not just a reply.
How long until we see results? Expect 4-8 weeks for setup, warmup, and initial campaigns. Anyone promising day-one results is overselling.
What happens if it's not working? Good agencies adjust strategy, messaging, and targeting. Bad ones keep running the same playbook.

B2B lead generation agencies can transform your pipeline when you pick the right partner. The key is matching the agency's strengths to your specific needs, budget, and target market.