Background Meeting Recruitment goals in a research study can be challenging. Recruitment for pedigree-based research, in which data and DNA are collected from genetically important family members, is especially difficult. The Familial Intracranial Aneurysm (FIA) study is a multicenter international study whose goal is to identify genetic and other risk factors for the formation and rupture of intracranial aneurysms (IAs). The chosen sites for the study are major referral centers for the diagnosis and treatment of IAs. In this analysis, we sought to determine what factors caused a recruited family to be incomplete, and what impact the methods used in identifying families had on the successful completion of family enrollment. Methods Three recruitment strategies were utilized to identify and enroll families: prospective monitoring of every new case of IA, subarachnoid hemorrhage, or intracranial hemorrhage; retrospective review of IA cases; and advertisement on the Internet, in scientific journals, and at professional meetings. An unexpected additional source of recruitment was exposure to the study through the news media. To help with public accessibility to the study, a web site and toll free number were established. Families were eligible for the study if they fit one of 4 patterns: [1] ≥2 living siblings affected with IA; [2] ≥2 affected siblings, 1 living and 1 genotype reconstructed from living spouse and children; [3] ≥3 affected members, 2 living and 1 reconstructed; [4] ≥ 3 affected members, 1 living, ≥1 reconstructed, and ≥1 living connecting relative. Exclusion criteria included fusiform-shaped IA; IA part of an AVM; family history of polycystic kidney disease; Ehlers-Danlos, Marfan, or moyamoya syndrome; fibromuscular dysplasia; or failure to obtain informed consent. Results Between 8/2002 and 10/2007, 3771 IA patients were screened for family history, and 681 potential families were identified, of which 441 successfully completed enrollment. There were 240 families which did not complete enrollment, due to refusal to participate (97), inability to locate needed relatives (87), exclusion criteria (50), no reason documented (5), and duplication (1 recruited at two sites). Completion of study enrollment was not significantly different by recruitment category (p=.17): 191 of 311 prospectively-recruited (61%), 66 of 89 retrospective (74%), 95 of 145 advertisement (66%), and 89 of 136 methods not documented (65%) families successfully completed enrollment. Conclusion In our study, the major reason for family exclusion was the inability to enroll needed family members, through refusal or failure to locate. All three methods used to identify potential families were successful in completing eligible families. The combination of recruitment strategies can be effectively implemented in future studies.