Objective: To document rates of adhesion development after abdomino-pelvic surgery, stratified by adhesion type, access method, and use of crystalloid solution instillates. Design: Reports from a MEDLINE search (1/1/1966-12/18/1996) detailing rates of adhesion development and meeting the inclusion criteria were subjected to meta-analysis. Setting: Meta-analysis. Patient(s): Patients undergoing abdomino-pelvic surgery. Intervention(s): Intraperitoneal crystalloid solution instillates. Main Outcome Measure(s): Percentage adhesion-free outcome in patients ("patients") or surgical sites ("sites"). Result(s): Adhesion-free outcome (sites) was lowest for reformed (26.3% laparotomy; 14.3% laparoscopy), higher for de novo Ib (direct trauma) (45.2% laparotomy, 37.2% laparoscopy), and highest for de novo la (indirect trauma) adhesions (82.4% laparoscopy). Crystalloid solution instillates reduced adhesion-free outcome at sites (45.2% versus 20% de novo Ib adhesions in laparotomy) and in patients (43.5% versus 19.9% reformed, laparotomy; 71.7% versus 25% de novo Ib, laparoscopy). Conclusion(s): Adhesion-free outcome was lowest for reformed, higher for de novo Ib, and highest for de novo la adhesions. Surprisingly, it was lower in laparoscopy than in laparotomy for de novo Ib and reformed adhesions. Crystalloid instillates did not increase adhesion-free outcome. Although limited by the retrospective and heterogeneous nature of the data, these conclusions nonetheless provide a basis on which to formulate future hypotheses. (Fertil Steril(R) 1998;70:702-11. (C) 1998 by American Society for Reproductive Medicine.).