Perceived risk and representations of cardiovascular disease (CVD), and preventive behaviour of people diagnosed with Familial Hypercholesterolemia by DNA testing (N = 81) were assessed. In general, participants perceived their own CVD risk as being relatively low. While participants reported almost optimal medication adherence (99%), only 49 per cent reported following recommendations concerning diet and physical activity. Family history of CVD was associated with both risk perception and the adoption of a healthy lifestyle. In their communications with FH-screened positives, health professionals should be aware that people may underestimate CVD risk, and should stress how behaviour change can reduce the risk.