As artemether/lumefantrine is now deployed as the first-line treatment for uncomplicated falciparum malaria in Bangladesh, information on its efficacy and adherence to its use is important. A randomised controlled non-inferiority trial comparing directly observed treatment (DOT) and non-directly observed treatment (NDOT) was conducted in 320 patients with uncomplicated falciparum malaria in Bandarban Hill Tract District, Bangladesh. Both regimens showed similar high levels of PCR-corrected 42-day parasitological and clinical cure rates (99.3% in the NDOT group and 100% in the DOT group; P=0.49). Survival analysis for the time to recurrence of infection showed no difference between treatment groups (log rank, P=0.98). Adherence, as assessed by counting remaining tablets and oral interviews, was 93% in the NDOT group and was confirmed by Day 7 lumefantrine concentrations. Adherence was independent of educational level. Patients with plasma lumefantrine concentrations < 280 ng/ml at Day 7 were at greater risk for re-infection (relative risk 5.62; P=0.027). The efficacy of artemether/lumefantrine for the treatment of uncomplicated falciparum malaria in Bangladesh is high and is similar for DOT and NDOT. Adherence to therapy is high.