Background: Most Chagas patients belong to the chronic indeterminate stage, in which pharmacological treatment has an inconclusive outcome. Objective: To evaluate the effi cacy of nifurtimox treatment in chronic asymptomatic Trypanosoma cruzi infection. Methods: We performed a systematic review and meta-analysis of electronically published literature, with no language, type of study, age or gender restrictions, until September 2010. Studies of chronic asymptomatic Chagas disease patients treated exclusively with nifurtimox were included in the analysis. Treatment effi cacy was evaluated using parasitological or serological parameters. Results: Of 463 identifi ed studies, 7 were fi nally selected: 6 observational studies and 1 randomized clinical trial; 4 of the studies were in adults, 3 in children < 14 years. In 6 studies, outcomes were defi ned by serological techniques. Summary estimate (log odds) was 0.37 (CI 95% -1.32 -2.07). Conclusions: The analyzed studies gave discordant results. Those might be explained by differences in the populations studied, follow-up periods, diagnostic techniques, and sample size. More studies are necessary to obtain conclusive results about treatment effi cacy of nifurtimox in this clinical phase of T. cruzi infection.