Comparison between membrane markers and enzyme markers was made in 74 cases of non-Hodgkin's malignant lymphomas and a good correlation appears between both methods in order to distinct lymphomas into T and B origin. Enzyme markers are reliable and provide quickly made and easily interpretable documents. As far as T-lymphomas are concerned, three hydrolases namely acid phosphates e, acid esterase and B-glucuronidase give the same good results. As for B-lymphomas, a specific enzyme marker has to be found. Furthermore, typing of malignant lymphomas by enzymatic and/or immunologic methods appears to be quite better than from morphologic features such as convoluted or cleaved nuclei for example.