Individuals with a family history of colorectal cancer (CRC), have a two-to-five-fold increased lifetime risk to develop CRC. Thus, they are particularly likely to benefit from adherence to medical recommendations for CRC prevention. Despite this increased risk, previous studies have shown an underutilization of colonoscopy for screening and a paucity of data on lifestyle habits that could enhance colonoscopy rates in this population. The primary aims were (a) to assess CRC screening patterns and lifestyle choices among siblings and children of CRC patients, (b) to ascertain discrepancies between actual behavior and medical recommendations, and (c) to identify family members with multiple unhealthy lifestyle habits. The secondary aim was to test for possible associations between utilization rates for CRC screening and other preventive health services. A cross-sectional study was conducted among 318 first-degree relatives (FDRs) of 164 CRC patients treated at the Tel Aviv Sourasky Medical Center. Interviews were conducted with a structured questionnaire. There was significant underutilization of colonoscopy for screening with only 73 FDRs (23.0%) adhering to the recommended screening schedule. This rate was slightly improved (N = 58, 31.9%) among subjects aged 40 years and above, although it was still far below the optimum. A similar result (N = 70, 21.7%) was observed for other cancer screening tests and routine medical check-ups. A significant association (P < 0.0001) was found for healthful lifestyles, overall use of preventive health services, and adherence to CRC screening recommendations. CRC screening is significantly underutilized among FDRs of CRC patients. FDRs who do not comply with CRC screening guidelines, lead unhealthy lifestyles, and avoid other cancer screening tests are at increased risk and should be addressed specifically in future interventions.