OBJECTIVE To determine the frequency of membranous glomerulonephritis(MGN) in the renal biopsy specimens. To observe the presenting features and the demographics to determine association, if any, between MGN and hepatitis B in these patients. METHODS Descriptive study. METHODS The section of histopathology, The Aga Khan University Hospital, Karachi over a period of three years (May 1999-April 2002). METHODS All consecutive percutaneous renal biopsy specimens received during the study period were included. A total of 1590 renal biopsy specimens were evaluated. All cases where a definitive diagnosis of MGN (stage II to IV) was made on light and/or immunofluorescence studies were included in the results. Twenty-eight cases were excluded owing to inadequate material. Cases with a presumptive diagnosis and those in stage I of MGN were also excluded. Laboratory investigations carried out include urine examination, blood urea nitrogen. (BUN), serum creatinine, 24 hours urinary protein, Hepatitis B sAg, serological tests for hepatitis C virus, ANA, dsDNA, etc. Clinical features and results of laboratory analysis were recorded along with light microscopic features and statistical analysis was carried out. RESULTS Out of 1562 renal biopsy specimens, 835(53.4%) cases showed primary glomerular pathology. 741(47.4% of the total) cases presented with nephrotic syndrome. Out of these in 176 cases (23.75%), findings were those of membranous glomerulonephritis followed by amyloidosis and focal segmental glomerulosclerosis. Among the cases with MGN, 23(13%) cases were those of secondary MGN whereas 87% were grouped under primary MGN. The male to female ratio was 2.2:1. Mean age at presentation was 29 years, median 29 years and a mode of 30 years. Nineteen cases (1.07%) were seen in children of 14 years old or less. CONCLUSIONS The frequency of MGN was much higher in our study subjects as compared to most other regional studies. No significant association with hepatitis B was seen with only 4 out of 89 cases showing positivity for HBsAg. The pattern of disease corresponds more to that seen in the west.