We study the venture performance effects of Venture Capital (VC) due diligence—i.e., the process through which VCs scrutinize ventures for potential investment. Our novel data comprises nearly 2,000 startups applying for funding to a UK VC seed fund (Fund). For identification, we exploit the Fund’s process of screening applicants for due diligence, which features pre-determined selection rules based on the scores of randomly allocated reviewers. We show that assignment to due diligence leads to substantial increases in venture capital fundraising and growth within two years of application, even for those firms that receive no eventual investment from the Fund. The due-diligence performance effects do not vary systematically across observable or unobservable applicant characteristics. By contrast, we find little evidence of venture performance effects from applicants’ assignments to informal Fund meetings that are not part of the due diligence process. The results provide evidence that going through VCs’ due diligence process adds value in the form of improved venture performance through three potential mechanisms: certification, coaching and self-validation. This new evidence implies that VCs’ role in innovation affects many more firms, as it goes beyond their value-added effects on portfolio companies in which they invest. Therefore, frictions in the process through which startups seek and obtain VC due diligence can profoundly impact innovation and economic growth.