Introduction: Physical activity is one of the basic needs for toddlers because it can been shown to potentially benefit children’s physical, social and cognitive growth. Acute diseases are very common among toddlers, especially in Sub-Saharan Africa. The purpose of this study was to compare activity of healthy and acutely ill toddlers. Methods: This study was a secondary analysis of the iLiNS-DOSE trial, which took place in Malawi during 2009-2012. The ActiGraph GT3X+ accelerometer was used to measure physical activity. Morbidity measurements were collected into a form by a research assistant together with a guardian’s verbal report, based on the already filled Morbidity calendar. Days during which a child was suffering from any symptoms of diarrhoea, fewer or acute respiratory infection were counted as sick days. The main activity outcome was mean vector magnitude accelerometer counts/15s. The secondary outcome was % time spent in moderate-to-vigorous physical activity by the vertical axis. We compared the activity of a sick day and a healthy day in within-children and between children. Results: Altogether 1 932 participants were enrolled in the iLiNS-DOSE study, 279 children were included in this sub-study and contributed to 843 (41%) days with symptoms (297 participants of withinchildren and between-children analyses and 729 participants of all healthy or sick during the measurement week analyses). We found the mean accelerometer counts on the within-children analysis in healthy days 303, SD 67 and on days with symptoms 305, SD 70 (difference 2, 95% Cl -6 to 3, p=0.48). The mean accelerometer counts on between-children analysis in healthy days 305, SD 79, and on days with symptoms 303, SD 76, (difference - 2, 95% Cl -4 to 10, p=0.43). Conclusion: No difference was found in physical activity between days with acute diseases and days withoutn symptoms among Malawian toddlers.