AbstractThis study aimed to quantify the burden of relapse following successful treatment for uncomplicated severe acute malnutrition (SAM) and to identify associated risk factors in rural Niger. We used data from 1490 children aged 6−59 months discharged as recovered from an outpatient nutritional programme for SAM and followed for up to 12 weeks after admission. Postdischarge SAM relapse was defined as weight‐for‐height Z‐score <−3, mid‐upper arm circumference (MUAC) <115 mm or bipedal oedema after having been discharged as recovered. Postdischarge hospitalisation was defined as admission to inpatient SAM treatment or hospitalisation for any cause after having been discharged as recovered. We used multivariate log‐binomial models to identify independent risk factors. After programmatic discharge, 114 (8%) children relapsed to SAM and 89 (6%) were hospitalised. Factors associated with SAM relapse were discharge during the lean season (relative risk [RR] = 1.80 [95% confidence interval [CI] = 1.22−2.67]) and larger household size (RR = 1.56 [95% CI = 1.01−2.41]), whereas older child age (RR = 0.94 [95% CI = 0.88−1.00]), higher child MUAC at discharge (RR = 0.93 [95% CI = 0.87−1.00]) and maternal literacy (RR = 0.54 [95% CI = 0.29−0.98]) were protective factors. Discharge during the lean season (RR = 2.27 [95% CI = 1.46−3.51]) was independently associated with postdischarge hospitalisation. Future nutritional programmes in the context of Niger may consider modification of anthropometric discharge criteria or the provision of additional home support or follow‐up during the lean season as potential interventions to prevent relapse. More research including postdischarge follow‐up is needed to better understand the sustainability of treatment outcomes after discharge and the type of intervention that may best sustain recovery over time. Clinical Trial Registration: ClinicalTrials.gov number, NCT01613547.