Seventy cases of follicular B-cell lymphomas were studied: 37 cases derived from the follicular centre [27 centroblastic-centrocytic (CB-CC) and 10 centroblastic (CB)] and 33 from the mantle zone [mantle-cell lymphoma (ML)]. Presenting features as well as response to therapy, time free of symptoms and survival were reviewed. All the cases were diagnosed and classified with routine and immunohistochemistry methods. In 61 cases tumors were studied with specific markers in a CAS-200 Image Analyser. Flow cytometry (FCM) was also done and correlated with proliferative-values and survival. A minor aggressive course of CB-CC and ML was demonstrated, with ML being the most benign form (lower proliferation rate and longest survival). Ploidy did not correlate with histological subtypes, survival or response to therapy. These results confirm the utility of biodynamic studies in lymphoid neoplasias.