To determine the pattern of diseases that are responsible for lymph node biopsy, a retrospective study was carried out by reviewing daily register and pathologic reports for surgical biopsy specimens for the year 1981-1990 in the Department of Pathology, Medical Faculty, Addis Ababa University. Among 33,924 biopsy specimens 3,396 (10%) were lymph node biopsies (1,378 females, 2018 males). The results showed that 57% were cervical, 15.17% axillary and 8.7% inguinal lymph nodes. The three main causes of lymphadenopathy were tuberculosis (47.8%), reactive lymphadenopathy (26.3%) and malignant lesions (19.8%). In general this study has shown that the majority of lymphadenopathies in patients under 40 years of age are mainly due to tuberculosis and non specific (reactive) lesions and we think this may serve as a basic information for clinicians in their daily activities.