The purpose of this study was to examine associations between screen time (ST) parenting practices and 2-5-year-old children's TV viewing and weight status. Data were collected from 252 parent-child dyads enrolled in a randomized parent-focused childhood obesity prevention trial from 2009-2012. ST parenting practices were assessed at baseline using a validated parent-reported survey. Parent-reported child TV viewing and objectively measured anthropometrics were assessed at baseline, post-intervention (35 weeks), and follow-up (59 weeks). Marginal effect models were developed to test the association between baseline ST parenting practices and children's TV viewing, BMI z-score, and waist circumference across all time points. Limiting/monitoring ST was associated with decreased weekly TV viewing (β = -1.79, 95% CI: -2.61; -0.95), while exposure to TV was associated with more weekly TV viewing over 59 weeks (β = 1.23, 95% CI: 0.71; 1.75). Greater parent use of ST as a reward was associated with increased child BMI z-score (β = 0.15, 95% CI: 0.03; 0.27), while limiting/monitoring ST was associated with decreased BMI z-score (β = -0.16, 95% CI: -0.30; -0.01) and smaller waist circumference (β = -0.55, 95% CI: -1.04; -0.06) over the study period. These findings suggest that modifying parent ST practices may be an important strategy to reduce ST and promote healthy weight in young children.