Limited evidence is available on the impact that unconditional cash transfer (UCT) programs can have on child nutrition, particularly in West Africa, where child undernutrition is still a public health challenge. This study examined the impact of a multiannual, seasonal UCT program to reduce the occurrence of wasting (weight-for-height, midupper arm circumference), stunting (height-for-age), and morbidity among children <36 mo old in Tapoa Province, in the eastern region of Burkina Faso. The study was designed as a 2-arm cluster-randomized controlled trial, with 32 villages randomly assigned to either the intervention or the control group. The study population comprised households that were classified as poor or very poor according to household economy approach criteria and that had ≥1 child <1 y of age at inclusion. The intervention consisted of seasonal UCTs, provided monthly from July to November, over 2 y (2013 and 2014). A monthly allowance of 10,000 West African Financial Community of Africa francs (∼US$17) was given by mobile phone to mothers in participating households. Anthropometric measurements and morbidity were recorded on a quarterly basis. We found no evidence that multiannual, seasonal UCTs reduced the cumulative incidence of wasting in young children [incidence rate ratio: 0.92 (95% CI: 0.64, 1.32); = 0.66]. We observed no significant difference ( > 0.05) in children's anthropometric measurements and stunting between the 2 groups at the end point. However, children in the intervention group had a lower risk [21% (95% CI: 18.6%, 21.3%); < 0.001] of self-reported respiratory tract infections than did children in the control group. We found that seasonal UCTs in the framework of safety nets did not result in a significant decrease in the incidence of acute malnutrition among children in Tapoa Province. Cash transfers combined with complementary interventions targeted to child nutrition and health should be investigated further. This trial was registered at clinicaltrials.gov as NCT01866124.