A light, electron and immunofluorescence microscopy study was performed on 102 consecutive patients on whom suitable percutaneous renal biopsies were obtained. In this selected group of patients primary IgA glomerulonephritis was diagnosed in 6 (5.9%) cases. On light microscopy the glomerular lesions were predominantly focal (WHO class III) and diffuse mesangial proliferative glomerulonephritis (Class IV). The mesangial deposits showed high association with IgM deposits and presence of early complement components (C1q, C4) indicative of both classical and alternative pathways of C3 activation in our patients. The high incidence of nephrotic syndrome with microhaematuria (5 cases) is due to patient selection when compared to other studies. This study shows the existence of IgA nephropathy in Pakistan and larger number of cases need to be investigated to determine the true prevalence of this disease and its clinical manifestations and importance in Pakistan.