OBJECTIVE: To identify predictors of prolonged symptoms in athletes who sustain concussions. STUDY DESIGN: This was a multicenter prospective cohort study of patients in 2 sport concussion clinics. Possible predictors of prolonged symptoms from concussion were compared in 2 groups, those whose symptoms resolved within 28 days and those whose symptoms persisted beyond 28 days. Candidate predictor variables were entered into a logistic regression model that was used to generate aORs. RESULTS: A total of 182 patients met the inclusion criteria during the study period. The mean patient age was 15.2 +/- 3.04 years. More than one-third of the patients (n = 65) underwent computerized neurocognitive testing on their initial visit. On univariate analyses, Post-Concussion Symptom Scale (PCSS) score and all composite scores on computerized neurocognitive testing were apparently associated with prolonged symptom duration. Sex, age, loss of consciousness at time of injury, and amnesia at time of injury were not associated with prolonged symptom duration. After adjusting for potential confounding, only total PCSS score was associated with the odds of suffering prolonged symptoms. CONCLUSION: Further efforts to develop clinical tools for predicting which athletes will suffer prolonged recoveries after concussion should focus on initial symptom score.