The purpose of this study carried out in two adjacent areas of the coastal mangrove forest of Guinea (Dubreka and Boffa) was to screen the population for disease, provide information on human African trypanosomiasis (HAT, a.k.a. sleeping sickness) and compare the epidemiologic and clinical features with those of outbreak areas in the Ivory Coast where more data is currently available. Cases of HAT were confirmed by parasitological testing after active medical work-up (91 of 9637 patients examined). Five cases were confirmed in patients in treatment centers. Of the first 57 cases admitted for treatment in the Dubreka and Boffa centers, 29 were responded to a clinical and epidemiological questionnaire and underwent thorough clinical examination. Disease stage was determined by cytochemical testing of cerebrospinal fluid. As in outbreak areas of the Ivory Coast, sleeping sickness in Dubreka and Boffa is a rural disease mainly affecting the working population. Most cases identified in Guinea involved men and women working in farming, fishing, or salt extraction. However unlike Ivory Coast outbreak areas where ethnic diversity related to share cropping is considered to play a major role in maintaining endemicity, almost all patients in our study (98%) were from the native Soussou population that is self employed and lives in villages with no immigrant population. While clinical symptoms observed in these patients were not different from those reported elsewhere, there was a high frequency of cervical adenopathy (93%). This finding could provide a useful diagnostic sign for screening populations living in these mangrove forest regions and as a source for parasitological diagnosis as shown by the fact that 88.5% of patients were screened on the basis of lymph node fluid specimens. Most patients including among those identified by active work-up (5%) were in the meningo-encephalitis phase of the disease (98%). The findings of this study underline the need not only to continue surveillance in these regions but also to extend surveillance throughout the country as a means of avoiding recrudescence and extension of the disease.