The present study aimed to determine the 6-month incidence of relapse and associated factors among children who recovered from acute malnutrition (AM) following mid-upper arm circumference (MUAC)-based simplified combined treatment using the ComPAS protocol. A prospective cohort of 420 children who had reached a MUAC ≥ 125 mm for two consecutive measures was monitored between December 2020 and October 2021. Children were seen at home fortnightly for 6 months. The overall 6-month cumulative incidence of relapse [95%CI] into MUAC < 125 mm and/or edema was 26.1% [21.7; 30.8] and 1.7% [0.6; 3.6] to MUAC < 115 mm and/or edema. Relapse was similar among children initially admitted to treatment with a MUAC < 115 mm and/or oedema and among those with a MUAC ≥ 115 mm but <125 mm. Relapse was predicted by lower anthropometry both at admission to and discharge from treatment, and a higher number of illness episodes per month of follow-up. Having a vaccination card, using an improved water source, having agriculture as the main source of income, and increases in caregiver workload during follow-up all protected from relapse. Children discharged as recovered from AM remain at risk of relapsing into AM. To achieve reduction in relapse, recovery criteria may need to be revised and post-discharge strategies tested.