Three two‐year datasets of ano‐genital signs were collected for comparisons of the injuries seen with accidental trauma and child sexual abuse in children less than 16 years of age: (1) Those attending a regional children's emergency department (South East Scotland) (n = 146) for injuries to the ano‐genital area; (2) all admissions to hospital in Scotland for straddle injury (n = 56); and (3) all children attending a regional child abuse and neglect service for assessment of suspected child sexual abuse (n = 98). Accidental injury types were combined for comparison with abusive injuries. ‘Three two‐year datasets of ano‐genital signs were collected for comparisons of the injuries seen with accidental trauma and child sexual abuse’ In South East Scotland, 1:1785 children under 16 years will attend an emergency department and 1:9305 will be admitted annually for an ano‐genital injury. In boys, penile and scrotal injuries were only seen following accidents; anal injury was more frequent following suspected abuse (36%) than after accidents (5%). In girls, injuries to the perineum and labia were more frequent after accidental trauma (32% and 74%, respectively, compared to 2% and 11% following suspected abuse), while hymenal injuries were more frequent after sexual abuse (19% compared to 1% in the accident group). Acute injuries to the posterior fourchette were common from both causes, (17% accidents and 10% abuse) and vaginal injuries were uncommon in both groups (5% accidents and 2% abuse). The sites of injury may assist in the differential diagnosis of the cause in ano‐genital injuries. Copyright © 2017 John Wiley & Sons, Ltd Key Practitioner Messages Hymenal or vaginal injury is very unlikely in accidental ano‐genital injury unless there are indications of significant impalement. Perineal and labial injuries are very common in accidental ano‐genital injury. Injuries to the posterior fourchette poorly differentiate abusive and accidental ano‐genital injuries. In boys, penile and scrotal injuries are more common following accidental injury, whereas anal/perianal injuries are more likely abusive.