In a comparative study of prevalence of asymptomatic bacteriuria in a Thai population, 1.4% of 955 apparently healthy adults (12 female and 1 male) were found to have positive urine culture. Of these, 6 individuals grew staphylococcal coagulase-negative, 3 grew E. coli, and the rest grew various other organisms. Among 176 patients with glomeruionephropathies (GNP), 20.5% (17 male and 16 female) yielded positive urine cultures. These included 18 positive for E. coli, 3 for staphylococcal coagulase-negative, 5 for Klebsiella and 3 for Enterobacter; the rest grew various other organisms. There was a higher overall prevalence of asymptomatic bacteriuria in GNP when compared to the controls. Heavy proteinuria is also a predisposing factor for an increase in the prevalence of asymptomatic bacteriuria in female GNP only.