To determine effects of the 5-4-3-2-1 Go! community social marketing campaign on obesity risk factors. We randomly assigned 524 parents of 3- to 7-year-old children to receive 5-4-3-2-1 Go! counseling or not. We surveyed parents about 5-4-3-2-1 Go! behaviors and perceptions of children's behaviors at baseline and one year later. We conducted multivariable logistic regression for each outcome. Parents who received counseling consumed more fruits and vegetables at follow-up (OR 1.749, [95% CI: 1.01-3.059]). Parental exposure to messaging at children's school events was associated with higher water consumption (6.879, [1.954-24.212]). 5-4-3-2-1 Go! is a promising intervention.