Background &Aims: Periodic colonoscopy is an effective means of reducing the incidence and mortality of colorectal cancer in individuals with a family histor y of the disease. The aims of this study were to determine the degree of complia nce and to identify the factors related significantly to noncompliance with peri odic screening in this high-risk population. Methods:A total of 178 individuals who had undergone genetic couns eling for colorectal cancer between 1986 and 1998 and who had been advised to un dergo periodic screening because of familial colorectal cancer (FCRC) or heredit ary nonpolyposis colorectal cancer (HNPCC) were invited to complete a self-repo rt questionnaire on psychosocial issues and screening experiences.Compliance dat a were derived from medical records and via self-report. Results: A total of 14 9 individuals (84%) participated in the study. Noncompliance with screening adv icewas rare (in 3%of cases), but significant delays (more than 1 year) in under going screening were observed in approximately 25%of the cases. The number of p erceived barriers to screening (eg, discomfort, embarrassment) was the only vari able related significantly to noncompliance/screening delay (odds ratio, 1.2;95 %confidence interval, 1.1-1.3). Use of sedatives during the procedure and rece ipt of a reminder letter seemed to facilitate better compliance. Conclusions: Al though few high-risk individualsabstain from screening entirely, approximately one in 4 deviates significantly from the recommended frequency of screening. Inc reased compliance may be achieved by reducing the discomfort and embarrassment a ssociated with the procedure and by the use of reminder letters. Background & Aims: Periodic colonoscopy is an effective means of reducing the incidence and mortality of colorectal cancer in individuals with a family histor y of the disease. The aims of this study were to determine the degree of complia nce and to identify the factors related significant significantly to Methods: A total of 178 individuals who had undergone genetic couling for colorectal cancer between 1986 and 1998 and who had been advised to un dergo periodic screening because of familial colorectal cancer (FCRC) or heredit ary nonpolyposis colorectal cancer (HNPCC) were invited to complete a self-repo rt questionnaire on psychosocial issues and screening experiences. Compliance dat a were derived from medical records and via self-report. Results: A total of 14 9 individuals (84 %) participated in the study. Noncompliance with screening adv icewas rare (in 3% of cases), but significant delays (more than 1 year) in under going The number of p erceived barriers to screening (eg, discomfort, embarrassment) was the only vari able related significantly to non compliance / screening delay (odds ratio, 1.2; 95% confidence interval, 1.1 -1.3). Use of sedatives during the procedure and rece ipt of a reminder letter seemed to facilitate better compliance. Conclusions: Al though few high-risk individuals abstain from screening entirely, approximately one in 4 deviates significantly from the recommended frequency of screening. Inc reased compliance may be achieved by reducing the discomfort and embarrassment a ssociated with the procedure and by the use of reminder letters.