This study aims to apply different methods for oueme-basin base flow assessment. Of the four separation hydrogam approaches of that exist for the assessment of the baseflow, only the approaches by filter proposed by Nathan & McMahon, Chapman and the one this of Furey and Gupta have been tested in view of an identification of the most suitable method for the evaluation of the baseflow. The application of the method «approaches by filter», watch that the filter of Nathan & McMahon gives some results very little satisfactory in spite of relatively weak values of mistakes. As for the filters proposed by Furey & Gupta, the gotten results present an overestimate of the baseflow during the period of the low flow. Only the filter proposed by Chapman shows a good evaluation of the baseflow all along the year. The method of Chapman is very comfortable and precise. It is evident from these works that the method of Chapman can be used to value the oueme baseflow. The results descended of its application can be used therefore like.