Histologic study of Bancroftian lymphadenopathy in 58 patients originating from an endemic area revealed a wide range of tissue reactions to the filarial worms. In seven patients (12.0%), no attendant inflammation or parasite damage was observed. A mild-to-intense nongranulomatous chronic lymphangitis was found in 12 patients (20.7%). Granulomatous reactions with variable composition were the most common pattern observed (37 patients, 63.8%); fibrotic lesions containing calcified worms were present in 13 of these patients. Epithelioid granulomas without worms, associated either with granulomatous reactions to the worms (seven patients) or nongranulomatous lymphangitis (two patients), were also detected. Lymphoid hyperplasia and lymphatic dilation were constant, and eosinophil infiltration was usually remarkable. These findings were compared with those reported from nonendemic populations and emphasize the parallelism between the pathologic findings and the immune responsiveness reported in such patients.