Objective: To analyze the available data on the efficacy of oral beta-agonist maintenance therapy in delaying delivery and in decreasing the incidence of preterm birth and its complications. Data Sources: A computer search of English-language abstracts using MEDLINE (medical subject heading terms: labor, premature and beta-adrenergic receptor agonist, therapeutic use) was supplemented with a review of the bibliographies of obstetric texts to identify randomized trials of oral beta-agonist maintenance therapy. Methods of Study Selection: Six trials were identified, of which four met our inclusion criteria for the meta-analysis. Data Extraction and Synthesis: Trials to be included in this meta-analysis underwent trial quality evaluation and data abstraction independently by two blinded investigators. An estimate of the odds ratio (OR) and risk difference was calculated for the dichotomous outcomes using both a random effects model and a fixed effects model. Continuous outcomes were pooled using a simple weighted average of the within-study difference in means. The pooled OR for preventing preterm delivery was 1.09 (95% confidence interval [CI] 0.60-1.99) and the OR for preventing recurrent preterm labor was 1.05 (95% CI 0.53-2.05). The pooled difference in the mean interval to delivery was -0.22 days (95% CI -2.5 to +1.99). Conclusions: The available data do not support a role for beta-agonist maintenance therapy after resolution of an acute episode of preterm labor in reducing the incidence of preterm delivery, increasing the interval to delivery, or reducing the incidence of recurrent preterm labor.