Within the framework of the Mobile Radiological TB Screening Unit of the Health Department of Paris (DASES), six migrant worker housing units were selected to benefit from the presence of a health care professional on-site. This presence would ensure that following a chest X-Ray, residents would be offered the possibility of an interview with a general practitioner about Schistosoma haematobium (Sch. h.) including: collection of a urine specimen on-site (microscopic detection of eggs performed at the lab the next day), and free medical consultation (CDO) in a neighbouring municipal free clinic proposed to people expressing a health problem. The objective is to assess feasibility and impact of screenings undertaken on-site and thereafter, within free clinics. CDO have been created for precarious populations by the DASES in 1998. 97 persons received an individual interview, of which 52 have undergone Sch. h. screening. 3 cases were found (5.7%). 57 persons went to the CDO out of 75 to whom it was offered (18 no-show). In total, 33 pathologies were detected among 24 patients: HBV infection (7 cases), Sch. h. (9 cases), intestinal parasitic infection (5 cases), sexually transmitted infection (2 cases), HIV-2 infection (1 case) and fewer non infectious diseases. The treatable diseases detected have all been treated free of charge. Community health services which involve screening and assessment by going directly to those persons in migrant worker housings is worthwhile for Sch. h. (although it is less efficient on-site than in CDO) and for HBV screening. This personalized, individual, and targeted contact supports the development trust and confidence of the migrants in order to then visit a GP and a social worker in a Municipal Clinic. But the follow-up of people diagnosed with a chronic disease is uncertain and costly for patients without full social security coverage. The continuation of such prevention programmes is recommended in such housing units