A comprehensive perinatal safety initiative (PSI) was incrementally introduced from August 2007 to July 2009 at a large tertiary medical center to reduce adverse obstetrical outcomes. The PSI introduced: (1) evidence-based protocols, (2) formalized team training with emphasis on communication, (3) standardization of electronic fetal monitoring with required documentation of competence, (4) a high-risk obstetrical emergency simulation program, and (5) dissemination of an integrated educational program among all healthcare providers. Eleven adverse outcome measures were followed prospectively via modification of the Adverse Outcome Index (MAOI). Additionally, individual components were evaluated. The logistic regression model found that within the first year, the MAOI decreased significantly to 0.8% from 2% (p<.0004) and was maintained throughout the 2-year period. Significant decreases over time for rates of return to the operating room (p<.018) and birth trauma (p<.0022) were also found. Finally, significant improvements were found in staff perceptions of safety (p<.0001), in patient perceptions of whether staff worked together (p<.028), in the management (p<.002), and documentation (p<.0001) of abnormal fetal heart rate tracings, and the documentation of obstetric hemorrhage (p<.019). This study demonstrates that a comprehensive PSI can significantly reduce adverse obstetric outcomes, thereby improving patient safety and enhancing staff and patient experiences.