Introduction: The advent of Diama and Manantali dams in the eighties has altered the schistosomiasis profile in the Senegal River Basin, with the appearance of an intestinal form in the Delta and a high prevalence of the urinary form in all ecological areas of the basin.Methods: The present study was mainly designed to re-evaluate the prevalence of schistosomiasis after many years of mass drug administration with praziquantel 600 mg allowing analysis of the pertinence of World Health Organisation guidelines in terms of dosing frequency, particularly in the Senegal River Basin. Stools and urine from 1,215 public school children from 24 villages identified in three ecological areas of the Senegal River Basin (Delta, valley, upper basin), were examined.Results: The results of this study show the endemic prevalences of urinary schistosomiasis in all ecological areas of the Senegal River Basin: 57.4% in the Delta, 32.5% in the Valley and 25.1% in the upper basin. The prevalence of the intestinal schistosomiasis form was 21.8 % in the Delta, and this form has also entered the valley.Conclusion: The results of this study confirm that schistosomiasis is still a public health problem in the Senegal River Basin despite several series of mass praziquantel 600 mg administration. This situation requires detailed reflection concerning dosing frequencies of this drug in the Senegal River basin and the need to take social behaviours and sociological realities into account in order to eradicate schistosomiasis.