OBJECTIVE: To estimate the effect of group prenatal care on perinatal outcomes compared with traditional prenatal care. DATA SOURCES: We searched MEDLINE through PubMed, EMBASE, Scopus, Cumulative Index of Nursing and Allied Health literature, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov. METHODS OF STUDY SELECTION: We searched electronic databases for randomized controlled trials and observational studies comparing group care with traditional prenatal care. The primary outcome was preterm birth. Secondary outcomes were low birth weight, neonatal intensive care unit admission, and breastfeeding initiation. Heterogeneity was assessed using the Q test and I 2 statistic. Pooled relative risks (RRs) and weighted mean differences were calculated using random-effects models. TABULATIONS, INTEGRATION, AND RESULTS: Four randomized controlled trials and 10 observational studies met inclusion criteria. The rate of preterm birth was not significantly different with group care compared with traditional care (11 studies: pooled rates 7.9% compared with 9.3%, pooled RR 0.87, 95% confidence interval [CI] 0.70-1.09). Group care was associated with a decreased rate of low birth weight overall (nine studies: pooled rate 7.5% group care compared with 9.5% traditional care; pooled RR 0.81, 95% CI 0.69-0.96), but not among randomized controlled trials (four studies: 7.9% group care compared with 8.7% traditional care, pooled RR 0.92, 95% CI 0.73-1.16). There were no significant differences in neonatal intensive care unit admission or breastfeeding initiation. CONCLUSION: Available data suggest that women who participate in group care have similar rates of preterm birth, neonatal intensive care unit admission, and breastfeeding.