Introduction and Aim. The aim of this study is to identify the predictors of early dropout of patients in methadone maintenance treatment (MMT) clinics in Yunnan province, China. Methods. A cohort study was conducted on 218 patients starting treatment in five MMT clinics between 1 March 2008 and 31 August, with follow up to 28 February 2009. Patients were interviewed using a semistructured questionnaire covering socio-demographic characteristics and drug abuse history. Attendance at clinic and daily dose were abstracted from the clinic records. The mean average daily dose per patient in each period was compared across three periods, 0-1, > 1-3 and > 3-6 months, using analysis of variance and random-intercept mixed linear regression modelling. Cox regression model with time-varying average daily dose within each period was performed to identify factors predicting dropout in the MMT program. Results. Cumulative probability of retention at 1, 3 and 6 months was 94%, 75% and 57%, respectively. There was no relationship between dose and probability of dropout in periods 1 and 2. However, after 3 months higher average daily dose (> 60 mg) was associated with lower probability of dropout. Dropout was more likely among the Han ethnic group [hazard ratio (HR) = 1.86, 95% confidence interval (CI): 1.65-3.26], in those who had to spend over 30 min to visit the clinic (HR = 1.63, 95% CI: 1.07-2.49) and in those living with other drug users (HR = 2.71, 95% CI: 1.55-4.74). Discussion and Conclusion. Patients' early dropout was related to ethnicity, clinic accessibility, living with drug users and methadone dose. A higher methadone dose as appropriate for maintenance treatment is recommended. [Che Y, Assanangkornchai S, Mcneil E, Chongsuvivatwong V, Li J, Geater A, You J. Predictors of early dropout in methadone maintenance treatment program in Yunnan province, China. Drug Alcohol Rev 2010].