To reduce child mortality in children younger than 5 years, Burkina Faso has been offering free care to this population of children since 2016. The free care program is aligned with the Integrated Management of Childhood Illness (IMCI) guidelines. Given that the number of studies that evaluated the competence of health-care workers (HCWs) during the free care program was limited, we assessed the adherence level of HCWs to the IMCI guidelines in the context of free care. This was a secondary data analysis. Data were obtained from a cross-sectional study conducted from July to September 2020 in 40 primary health-care centers and two district hospitals in the Hauts-Bassins region in Burkina Faso. Our analysis included 419 children younger than 5 years old who were consulted according to IMCI guidelines. Data were collected through direct observation using a checklist. The overall score of adherence of HCWs to IMCI guidelines was 57.8% (95% CI, 42.6-73.0). The mean adherence score of the evaluation of danger signs was 71.9% (95% CI, 58.7-85.1). The mean adherence score of following IMCI guidelines was significantly greater in boys (54.2%) compared with girls (44.6%; P < 0.001). Adherence scores of the performance of different IMCI tasks were significantly different across HCW categories. The overall adherence of HCWs to IMCI guidelines in the context of free care was greater than the adherence reported before the implementation of free care in Burkina Faso. However, this assessment needs to be performed nationwide to capture the overall adherence of HCWs to IMCI guidelines in the context of the free care program.