BACKGROUND Persistent diarrhoea (diarrhoea lasting more than 14 days) accounts for one third of all diarrhoea related deaths in developing countries in some studies. Probiotics may help treatment. OBJECTIVE To evaluate probiotics for treating persistent diarrhoea in children. METHODS In August 2010, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, EMBASE, and LILACS. We also contacted authors of included trials and organizations working in the field, and checked reference lists. METHODS Randomized controlled trials comparing a specified probiotic agent with placebo or no probiotic in children with persistent diarrhoea. METHODS Two review authors assessed the eligibility, risk of bias, extracted and analysed data. Differences were resolved by discussion. Statistical analysis were performed using the fixed-effect model and the results were expressed as mean difference (MD) for continuous outcomes with 95% confidence intervals (CI). RESULTS Four trials were included, with a total number of 464 participants; one trial had a low risk of bias. Meta-analysis showed that probiotics reduced the duration of persistent diarrhoea (mean difference 4.02 days, 95% CI 4.61 to 3.43 days, n=324, 2 trials). Stool frequency was reduced with probiotics in two trials. One trial reported a shorter hospital stay, which was significant, but numbers were small. No adverse events were reported. CONCLUSIONS There is limited evidence suggesting probiotics may be effective in treating persistent diarrhoea in children.