The aim of this study was to describe 2 years cancer survivors' perception of the cancer risk running in their family, and to describe how frequently these survivors recommended cancer screening to their relatives. A national cross-sectional survey was launched by the French Ministry of Health to investigate the living conditions of adult cancer patients 2 years after cancer diagnosis. Among the 13,923 patients identified, 6,957 were eligible to participate in this study and 4460 (64.1%) answered the questionnaire administered by telephone. One participant out of every two (50.8%) reported that they thought their relatives' risk of cancer was greater than that of the relatives of unaffected persons. Higher percentages were recorded among breast and colorectal cancer patients (65 and 65.1%, respectively), and lower percentages among those with lung and hematological cancer (34.9 and 28.4%, respectively). Overall, 61.1% of the participants had already advised relatives to undergo cancer screening and 10.4% planned to do so. Eighty-one percent of the participants with breast cancer and 76.3% of those with colorectal cancer said they had advised relatives to undergo screening. Lower percentages were obtained among patients with urinary tract (41.7%) and hematological malignancies (27.1%). Although patients' perceptions tend to fit the latest data on the frequency of cancer germline mutations, physicians should help their patients to convey more accurate advice to their families. If survivors were better informed, they could play a critical role by conveying relevant and sound risk reduction messages to their relatives.