Background Anderson-Fabry disease is an X-linked defect of glycosphingolipid metabolism. Progressive renal insufficiency is a major source of morbidity, additional complications result from cardio-and cerebro-vascular involvement. Survival is reduced among affected males and symptomatic female carriers. Objectives To evaluate the effectiveness and safety of enzyme replacement therapy compared to other interventions, placebo or no interventions, for treating Anderson-Fabry disease. Search methods We searched 'Clinical Trials' on The Cochrane Library, MEDLINE, EMBASE, LILACS and the Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Trials Register (date of the most recent search: 11 September 2012). The original search was performed in September 2008. Date of the most recent search of the Cystic Fibrosis and Genetic Disorders Group's Inborn Errors of Metabolism Trials Register: 11 September 2012. Selection criteria Randomized controlled trials of agalsidase alfa or beta in participants diagnosed with Anderson-Fabry disease. Data collection and analysis Two authors selected relevant trials, assessed methodological quality and extracted data. Main results Six trials comparing either agalsidase alfa or beta in 223 participants fulfilled the selection criteria. Both trials comparing agalsidase alfa to placebo reported on globotriaosylceramide concentration in plasma and tissue; aggregate results were non-significant. One trial reported pain scores, there was a statistically significant improvement for participants receiving treatment at up to three months, mean difference -2.10 (95% confidence interval (CI) -3.79 to -0.41); at up to five months, mean difference -1.90 (95% CI -3.65 to -0.15); and at up to six months, mean difference -2.00 (95% CI -3.66 to -0.34). There was a significant difference in pain-related quality of life at over five months and up to six months, mean difference -2.10 (95% CI -3.92 to -0.28) but not at other time-points. Neither trial reported deaths. One of the three trials comparing agalsidase beta to placebo reported on globotriaosylceramide concentration in plasma and tissue and showed significant improvement: kidney, mean difference -1.70 (95% CI -2.09 to -1.31); heart, mean difference -0.90 (95% CI -1.18 to -0.62); and composite results (renal, cardiac, and cerebrovascular complications and death), mean difference -4.80 (95% CI -5.45 to -4.15). There was no significant difference between groups for death; no trials reported on pain. Only one trial compared agalsidase alfa to agalsidase beta. There was no significant difference between the groups for any adverse events, risk ratio 0.36 (95% CI 0.08 to 1.59), or any serious adverse events; risk ratio 0.30; 95% CI 0.03 to 2.57). Authors' conclusions Six small, poor quality randomised controlled trials provide no robust evidence for use of either agalsidase alfa and beta to treat Anderson-Fabry disease.