Overnight radiology services (ORSs) provide computed tomography (CT) scan readings that are automatically reviewed by staff radiologists (SRs) and the trauma service. Discordant readings and their clinical significance were investigated.ORS-read CT scans over 3 years were reviewed. A discordant reading was clinically significant if it resulted in a substantive change in patient care. All clinically significant findings were reviewed by a blinded radiologist.Five hundred thirty-four CT scans were identified: 191 (35.8%) head, 187 (35%) cervical, 66 (12.4%) chest, and 90 (16.9%) abdomen/pelvis scans. One hundred twenty-three scans (23%) were abnormal with a DR of 16%: 5 head, 2 cervical, 7 chest, and 6 abdomen/pelvis scans. Seven (6%) scans had clinically significant findings missed: 3 head and 4 abdomen/pelvis scans. ORSs missed 7, and SRs missed 3 clinically significant findings. A blinded radiologist confirmed the clinically significant findings.The discordant rate of readings for abnormal CT scans was 16% with 37% considered to be clinically significant. ORSs missed 100%, and 29% of the clinically significant findings were identified after SR/trauma service rounds. SR/trauma service review of ORS readings is supported.