Clinical data and renal biopsy study of 186 adult patients found to have nephropathy and seen at the Security Forces Hospital, Riyadh, over a 5-year period (1989 to 1994) were reviewed. Primary glomerular disease accounted for more than three fourths of all patients (79%), and the most common histological lesion was focal segmental glomerulosclerosis (40.8%) associated with a high incidence of hypertension (86.7%), nephrotic syndrome (61.7%), hematuria (48.8%), and renal impairment (33.3%). Mesangioproliferative glomerulonephritis was the second most common lesion (21.1%), followed by membreous glomerulonephritis (13.6%), immunoglobulin A nephropathy (IgAN) (13.6%), membranoproliferative glomerulonephritis (9.5%), and minimal change disease (1.4%). Although not as common as in most other developed countries, IgAN is being increasingly recognized in Saudis. Lupus nephritis remained the commonest cause of secondary glomerulonephritis (48.5%), whereas amyloidosis was conspicuously absent. There is no evidence, at least in this series, that chronic infection such as hepatitis B virus infection has a major role in the development of glomerulonephritis.