This cross-sectional study examines the relationship between parenting stress and concerns identified by developmental screening and their effects on parents' decisions to seek medical care for their children. A total of 182 parents completed both the Parenting Stress Index (PSI) and the Parents' Evaluation of Developmental Status (PEDS) when their children were admitted to a sick child care program that provides parents the option of requesting medical evaluations for their children with mild acute illnesses. Although 31.6% of parents (N = 62) requested medical evaluations, neither PSI nor PEDS scores were associated with these requests. However, PEDS scores indicating significant parental concerns about their child's development or behavior predicted clinically significant levels of parenting stress on the PSI (odds ratio 4.9; 95% confidence interval, 1.5-15.9; P = .007). Primary pediatric health care providers who routinely perform developmental screening need to consider this relationship when interpreting developmental screening results and offer supportive and referral services to families as needed.