Purpose. Specific knowledge of the features of minor head trauma in infants is necessary to develop appropriate preventive strategies and adjust clinical management in pediatric emergency departments (PEDs). The aim of this study is to describe the epidemiology of minor blunt head trauma in infants <3 months who present to PEDs. Methods. We performed a prospective study of infants evaluated in any of 13 Spanish PEDs within 24 hours of a minor head trauma (Glasgow Coma Scale scores of 14-15) between May 2017 and November 2020. Telephone follow-up was conducted for all patients over the 4 weeks after the initial PED visit. Results. Of 1,150,255 visits recorded, 21,981 children (1.9%) sustained a head injury, 386 of whom (0.03%) were under 3 months old. Among the 369 patients who met the inclusion criteria (0.03%), 206 (56.3%) were male. The main causes of trauma were fall-related (298; 80.8%), either from furniture (138/298; 46.3%), strollers (92/298; 30.9%), or a caregiver’s arms (61/298; 20.5%). Most infants were asymptomatic (317; 85.9%) and showed no signs of injury on physical exam (210; 56.9%). Imaging studies were performed in 195 patients (52.8%): 37 (10.0%) underwent computed tomography (CT) scan, 162 (43.9%) X-ray, and 22 (6.0%) ultrasound. A clinically important traumatic brain injury (ciTBI) occurred in 1 infant (0.3% overall; 95% CI, 0-1.5), TBI was evidenced on CT scan in 12 (3.3% overall; 95% CI, 1.7-5.7), and 20 infants had an isolated skull fracture (5.5% overall; 95% CI, 3.4-8.3). All outcomes were caused by falls onto hard surfaces.Conclusions. Most head injuries in infants younger than 3 months are benign, and the rate of ciTBI is low. Prevention strategies should focus on falls onto hard surfaces from furniture, strollers, and caregivers’ arms. Optimizing imaging studies should be a priority in this population.