INTRODUCTION: Parks are an important component of the neighborhood environment, and their presence is believed to support higher levels of physical activity among residents. The present study examined park use frequency among a sample of 534 low-income parents of preschool aged children. Associations with child and parent physical activity, neighborhood characteristics and physical characteristics of the block immediately surrounding the home were examined. METHODS: Data are from baseline measurements completed in 2012-2014 as part of larger study (NET-Works: Now Everybody Together for Amazing and Healthy Kids) targeting low-income preschool children and their parents (N = 534 parent-child dyads). Physical activity was measured in parent and child using accelerometry. Parents reported their frequency of use with their child of parks within a half kilometer from their residence. Block audits were performed by trained research staff to describe the quality and walkability of the streets around the home. STATISTICAL ANALYSIS: Bivariate associations between demographic variables, perceptions of the neighborhood environment, parent support for child physical activity, and physical activity were examined using regression or Chi square analysis. RESULTS: Park use frequency was not significantly associated with child accelerometry light, moderate or vigorous physical activity. However, it was marginally significantly inversely associated with child accelerometry sedentary time (p < 0.06). Television viewing hours on weekend days (but not on weekdays) were significantly fewer among children in the high park use group compared with children who visited the park less frequently (p < 0.01). Park use frequency was significantly positively associated with parent accelerometry moderate physical activity (p < 0.004), and was significantly inversely associated with parent accelerometry sedentary time (p < 0.002). Frequent park use was significantly positively associated with parent report of the child frequency of being taken to a park or playground outside the home (p < 0.0001), past week visit to park and recreation center (p < 0.0001) and parent-reported supportive behaviors for child physical activity (p < 0.0001). Parents who reported having to cross busy streets to reach play areas reported less frequent park use (p < 0. 02). Walkable neighborhoods (p < 0.003) and more incivilities (p < 0.02) in the immediate block surrounding the home were significantly associated with more frequent park use. CONCLUSIONS: Frequent park use with their preschool child may support higher levels of physical activity among low-income parents and reduce sedentary time for both child and parent.