We noted in our practice of obstetric anesthesia at a large teaching hospital that the epidural catheter failure rate was higher than previously reported. We undertook this study to determine the incidence of epidural catheter failure in parturients and to determine the primary causes of failure. After institutional approval, we evaluated the charts of parturients who received epidural analgesia for labor or anesthesia for cesarean section for 6 randomly selected months spanning one year. We examined 4240 anesthesia records for patient-related data, operator-related data (years of training) and technical information. The participants were unaware there was a study in progress, and data were collected in a systematic fashion so as to minimize data collection related biases. Chi2, Mantel-Haenszel chi2, analysis of variance and univariate logistic regression were used to analyze data. P<0.05 was considered statistically significant. Overall epidural catheter failure rate was 13.1% with a dural puncture rate of 1.03%. The major causes of catheter failure were no analgesia and unilateral block. The experience of the anesthesiologist, the mode of delivery, patient age, patient weight, type of epidural catheter, occurrence of paresthesia and the use of CSE were all associated with significantly different epidural catheter replacement rates. Despite the initially high failure rate, the overall patient satisfaction rate was greater than 98%.