Morphological changes in lymph node biopsies of HIV-infected patients can be classified in four stages, based upon the degree of damage to follicular structures: (1) follicular hyperplasia, (2) follicular lysis, (3) follicular atrophy and (4) follicular and lymphocytic depletion. To define the relative usefulness of morphological, clinical and immunological findings for prognostic purposes, we followed the clinical evolution of 86 biopsied HIV+ patients for a period ranging from 1 to 56 months. A relatively good correlation between histological and clinical findings, at the time of biopsy, was observed. Statistical analysis confirmed the prognostic value of the histological features for clinical deterioration, progression to AIDS and survival. Moreover, histological findings gave more reliable prognostic information than clinical values. Our data suggest that lymph node biopsy can be utilized for prognostic purposes in the evaluation of the progression of the disease and effectiveness of antiviral therapeutic trials.