Background and Objectives. Early childhood screen time seems to persist into later childhood. This study examined the factors affecting the screen time change during the first two years of toddler's lives in Finland. We hypothesized that parents' sedentary behaviour and physical activity habits correlate significantly with children's screen time change. Methods. The data consists of 1797 mothers, 1658 fathers and their 1827 children from the STEPS Study (Steps to the healthy development) in Southwest Finland. Screen time change during the two-year follow-up was calculated for those (n = 634) who had both 13 and 36 months screen time measures (13 months, n = 940; 36 months, n = 845). Demographic correlates and parental behavioural correlates were measured with questionnaires, and anthropometric measurements in study visits. Results. The mean change in the children's screen time was a 55 min increase from 13 to 36 months. A linear mixed model analysis showed that the father's longer duration of sitting time was statistically significantly associated with a smaller increase in screen time of the child. Parents' physical activity was not associated with children's screen time change. The mother's advanced education, a younger age, and a lower screen time, the child attending day care and the child's lower body mass index were associated with children's smaller increase in screen time. Conclusion. The mother's advanced education as well as the father's sitting time, including sitting at the office, implied that children of higher educated parents have a smaller increase in screen time. Future studies should focus on studying why parental education has a greater influence on children's screen time change than parents' behaviour. (author abstract)