Increased intra-abdominal pressure represents a difficult problem when closing abdominal wall defects (AWD) and can cause renal insufficiency and vascular injury to the intestine with the development of necrotizing enterocolitis. Urinary bladder pressure measurements have been shown to accurately reflect intra-abdominal pressure in animal models. This study compares outcomes with and without vesical pressure measurements in AWD. Since its description in 1987, these vesical pressure measurements have guided the closure of AWDs. A pressure of <20 cm H2O allows closure by primary fascial, skin, or staged prosthetic closure. All charts of patients who underwent AWD closure from 1981 to 1993 were reviewed and data collected including type of defect and closure, gestational age, weight, age at operation, fluid requirements and urinary outputs, ventilator requirements, days to first and total feeding, total parenteral nutrition (TPN) days, hospital days, hospital charges, morbidity, and mortality. Results were analyzed by paired or unpaired Student's t test or Fisher's exact test. Twenty-seven infants did not receive vesical pressure measurements, whereas 13 did. No significant differences occurred in the parameters recorded in these two diverse groups. When gastroschisis patients only were compared, a significant decrease in intravenous fluid requirements in the vesical measurement group occurred on postoperative Day 2 (155.3+/- 37.5 versus 109.6 +/- 34.3; P = 0.016), and a significant decrease in urinary output occurred on postoperative Day 3 (4.2 +/- 112 versus 3.1+/- 1.1; P=0.044). Ventilator support, TPN days, and oral feeding data were all lower in the vesical measurement group but did not reach statistical significance. Hospital days and hospital changes showed a trend to lower values in the measured group (P values 0.052 and 0.095, respectively). Intraoperative vesical pressure measurements represent a simple, safe, effective method to guide the closing of AWD and result in less capillary leak and more prompt diuresis, and may result in significantly less morbidity, mortality, and cost.