The hospital records of 100 postpartal patients, deliveredper vaginam, were studied to determine if a relationship existed between factors of the ante-, intra-, and postpartal periods and the development of postpartal bladder atonia. The factors considered were: age, parity, pelvic configuration, frequency of intrapartal bladder emptying, length of labor, catheterization immediately prior to delivery, position of the presenting part, type of delivery, anesthesia used at delivery, and quantity of urine and elapsed time after delivery of the first postpartal bladder emptying.The risk of puerperal bladder atonia appeared to decrease as the patient's age increased; presumably this apparent trend was due to the small number of patients in the older age groups. It appeared, but could not be shown conclusively from these data, that bladder atonia decreased with increased parity.Those pelves associated with the highest incidence of bladder atonia were the gynecoid-gynecoid, gynecoid-android, and the anthropoid-anthropoid. No conclusions could be drawn regarding the effect of pelvic configuration on the development of postpartum bladder atonia. The absence of intrapartal bladder emptying bore no apparent relationship to the tonus of the postpartum bladder. No trend was found in evaluation of the length of labor, although it appeared that this factor was not etiologic in the development of bladder atonia.There was a greater incidence of postpartum bladder atonia in cases where the fetal vertex was positioned as occiput anterior. Nonetheless it could not be concluded that absence of bladder atonia among Patients where the occiput was positioned as transverse or posterior, or where the fetal breech presented, was significant. The absence of predelivery catheterization appeared to be of little significance in contributing to the development of the postpartum atonic bladder.The incidence of bladder atonia appeared greatest in patients delivered by operative means. Evaluation of anesthesia administered for delivery indicated that caudal analgesia apparently contributed to the development of bladder atonia in this study. There was no apparent trend shown in the postpartal voiding patterns that appeared etiologic in the loss of postpartal bladder tonus.