OBJECTIVES: To conduct a pilot study to assess the prevalence of blood-borne and sexually transmitted diseases (STDs) in a social-ly excluded Roma community engaging in risky behaviours in Brno, Czech Republic. METHODS: Fifty subjects engaging in risky behaviours, of whom 35 self-reported to belong to the Roma ethnicity, were recruited while receiving treatment in a newly established addiction centre in Brno between March and December 2017. All subjects were tested for blood-borne diseases and STDs. Epidemiological and demographic data were collected by means of assisted interview at the time of the first contact. RESULTS: Forty-three (86%) of 50 participants were anti-HCV positive. Of 35 subjects from the Roma subgroup, 32 (91.5%) tested anti-HCV positive. Among the 43 anti-HCV positive subjects, 35 (81.4%) also showed HCV RNA positivity. Of the 32 anti-HCV positive in the Roma subgroup, 26 (81.3%) were HCV RNA PCR positive. Only HCV (hepatitis C virus) genotypes 1 (a,b) and 3 were detected in the study group. Nine Roma subjects (25.9%)were newly diagnosed with syphilis of which none of them was aware. All study patients were negative for anti-HIV 1,2. CONCLUSION: As a proof of concept, this pilot study showed the importance of targeting epidemiological research and preventive care at excluded communities engaging in risky behaviours. The high anti-HCV seroprevalence in the Roma population in Brno who self-admitted intravenous drug use as well as the nine newly diagnosed cases of syphilis illustrate not only a high prevalence of risky behaviours in this excluded community but also the absence of systematic health care coverage in this population. A positive point is that when an appropriate model of care is used, even the Roma clients are willing and able to comply with the therapy. This is true of both viral hepatitis C and syphilis: thanks to close cooperation with addictology services and opiate substitution treatment, all nine patients successfully completed 2 weeks of anti-treponemal antibiotic treatment. More systematic work with socially excluded communities including specific models of care tailored to the needs of poorly compliant patients is an essential prerequisite for controlling HCV epidemics in the Czech Republic. An additional effect in the surveillance of other infectious diseases linked to risky behaviours can be considered as an added value.