Treatment success rates of rifampicin resistant (RR)/multi-drug resistant (MDR) tuberculosis (TB) in South Africa range from 43±48%, falling short of the World Health Organization’s target of 75%. We present rates and assess predictors of attrition by 12 months on treatment.Prospective observational cohort analysis of adults (18 years) initiating RR/MDR-TB treatment from 01 March 2013 to 30 September 2016. Attrition was defined as a combination of death and loss to follow-up (LTFU; treatment interruption 2 months) by 12 months on treatment. Predictors of attrition were identified using Cox Proportional Hazards models to estimate crude (HR) and adjusted hazard ratios (aHR) with corresponding 95% confidence intervals.By 12 months on treatment, 75/240 (31.3%) patients had either died (37/240; 15.4%) orbeen LTFU (38/240; 15.8%). Patients with moderate/severe anaemia (aHR: 2.10; 95% CI 1.00±4.39), and those who were smear positive at baseline (aHR: 2.04; 95% CI 1.01±4.12) were significantly more likely to die or be lost from care.