STUDY OBJECTIVE: Bruising can indicate abuse for infants. Bruise prevalence among infants in the pediatric emergency department (ED) setting is unknown. Our objective is to determine prevalence of bruising, associated chief complaints, and frequency of abuse evaluations in previously healthy infants presenting to pediatric EDs. METHODS: We conducted a prospective, observational, multicenter study of infants aged 12 months or younger presenting to pediatric EDs. Structured sampling was used. Pediatric emergency medicine clinicians performed complete skin examinations to screen for bruising. Study investigators documented skin findings, date of visit, patient's age, chief complaint, and abuse evaluation. The primary outcome was prevalence of bruising. Secondary outcomes were prevalence of bruising based on chief complaint and frequency of abuse evaluation. Point estimates of bruise prevalence and differences in bruise prevalence between patient subgroups were calculated with 95% confidence intervals (CIs). RESULTS: Bruising was identified in 88 of 2,488 infants (3.5%; 95% CI 2.9% to 4.4%). Rates of bruising for infants 5 months and younger and older than 5 months were 1.3% and 6.4%, respectively (difference 5.1%; 95% CI 3.6% to 6.8%). For infants 5 months and younger, 83% of bruising was associated with a trauma chief complaint and only 0.2% of infants presenting with a medical chief complaint had bruising. Pediatric emergency medicine clinicians obtained abuse evaluations on 23% of infants with bruising, and that rate increased to 50% for infants 5 months and younger. CONCLUSION: Bruising prevalence in children 12 months and younger who were evaluated in pediatric EDs was low, increased within age strata, and was most often associated with a trauma chief complaint. Most bruised infants did not undergo an abuse evaluation.