Introduction: Post-partum hemorrhage is a major cause of maternal mortality. Ultrasonography is a safe, rapid, and noninvasive diagnostic tool which can be used to identify and measure the abdomino-pelvic free fluid in post-partum period. Objective: This study was conducted to evaluate the risk factors and clinical significance of abdomino-pelvic free fluid after cesarean section. Method: Demographic data, indication of cesarean section, duration of operation, volume of intraoperative blood loss, and instability in vital signs, blood transfusion, decreased Hb level, and decreased urine output were documented in 100 women with cesarean delivery 4 and 24 h after surgery. Abdomino-pelvic free fluid volume was estimated by ultrasound study. Result: Four hours after cesarean, minimal, moderate, and large amount of free fluid was seen in 38(38%), 45(45%), and 17(17%) patients respectively. The volume of free fluid was decreased generally as 73 (73%) of patients had minimal amount of free fluid 24 h after surgery. There was statistically significant relationship between volume of blood loss during cesarean and the volume of free fluid 4 h (and not 24 h) after surgery. There was no statistically significant relationship between duration of operation and the volume of free fluid 4 and 24 h after cesarean. There is statistically significant relationship between free fluid volume 4 h after surgery and hemodynamic instability. Conclusion: Ultrasonography detects even minimal amount of free fluid in post-cesarean patients but cannot predict their clinical course. [ABSTRACT FROM AUTHOR]