United Kingdom (UK) guidelines recommend at least 18 months treatment for patients with multidrug-resistant tuberculosis (MDR-TB). Prior to 2008, data on treatment outcome were only available at 12 months and therefore the proportion completing treatment was unknown. This retrospective-prospective cohort study reports on treatment outcomes for MDR-TB patients notified between 2004 and 2007 and examines factors associated with successful outcomes. 70.6% (144/204) completed treatment in 24 months or more, 6.9% (14) stopped treatment, 6.9% (14) died, 7.8% (16) were lost to follow up, 0.5% (1) relapsed and 4.4% (9) were transferred overseas. Following adjustment for age, being non-UK born, non-compliance and having co-morbidities, treatment with a fluoroquinolone (OR 3.09; 95% CI 1.21-7.88; p<0.05) or bacteriostatic drug (OR 4.23; 95% CI 1.60-11.18; p<0.05) were independently associated with successful treatment outcome. Treatment completion for MDR-TB cases remains below the World Health Organization (WHO) target. Our findings support current WHO guidelines for MDR-TB treatment. The UK should consider adopting individualised regimens based on WHO recommended drugs, taking into account drug sensitivities. Improving treatment completion rates will be key to tackling further drug resistance and transmission from untreated infectious cases.