Ninety-two postpartum women who had been admitted to Siriraj Hospital from April 1, 1980 to March 1, 1983 were studied for the causative organisms of puerperal infection. Cervical and intrauterine swab & smear-gram stain as well as cultures were performed. Hemocultures were done in some cases. Only 50 per cent of all cases had positive cervical and intrauterine swab smears which showed different kinds of micro-organisms, 78 per cent were gram-positive cocci, gram-negative rod was found in 4 specimens, 2 specimens of gonococcal smears, one for trichomonads. Cervical and intrauterine swab cultures were positive in only 31.5 per cent. E. Coli was the most common and Staphylococci & Streptococci were the second most common.