During a 6 yr period, 105 (69%) of 153 patients in whom a histological diagnosis of minimal change glomerular disease was made had renal biopsy tissue suitable for immunofluorescence examination. Thirty seven (35%) patients showed glomerular mesangial deposits of IgM. All the patients presented with the nephrotic syndrome. We found no significant difference in age and sex prevalence, presentation, response to therapy and glomerular morphology between IgM positive and IgM negative groups. This study suggests that there is no necessity to categorize IgM positive minimal change glomerular disease as a separate entity.