Abstract Background Preschool children spend a significant proportion of their waking hours being sedentary. Parents play a critical role in developing and shaping their children’s lifestyle behaviours, particularly in the early years of life. This study aims to assess parental perceptions, attitudes and knowledge of their preschool children’s sedentary behaviours and the association with children’s television (TV)/video/DVDs viewing and total screen time. Methods Data were obtained from a sample of 4836 children (3.5–5.5 years), participating in the multi-centre ToyBox-study at baseline (T0) and at 1-year follow-up (T1) periods. Data on children’s sedentary behaviours were collected via a standardized proxy-administered primary caregiver’s questionnaire. Results Regarding total screen time, 66.6% of the children at T0 and 71.8% at T1 in the control group exceeded the recommendations, whereas the proportion in the intervention group varied from 69.7% at T0 to 72.5% at T1. The odds of exceeding total screen time recommendations were significantly higher when parental perceptions towards limiting the total screen time were negative [(both T0 and T1 and in the intervention and control groups (P < 0.05)]. Similarly, the odds of exceeding TV/video/DVDs viewing recommendations were significantly higher (both T0 and T1 is observed in both groups) when parental knowledge of recommendation were absent. Conclusions Preschool children whose caregivers stated rules limiting their sedentary screen time were less likely to spend a high amount of time watching TV/video/DVDs. Interventions to increase parental practices may be a promising approach to decrease total screen time of preschool children but studies are needed to confirm this.