Introduction We aimed to assess the number of “missed cases” in the detection of child abuse based on the Hague Protocol. This protocol considers 3 parental characteristics of ED adult patients to identify child abuse: (1) domestic violence, (2) intoxication, and (3) suicide attempt or auto-mutilation. Methods This study focuses on parents whose children should have been referred to the Reporting Centre for Child Abuse and Neglect (RCCAN) in the Hague, the Netherlands, according to the guidelines of the Hague Protocol. Data were collected from all referrals by the Medical Centre Haaglanden (Medisch Centrum Haaglanden) to the RCCAN in the Hague between July 1 and December 31, 2011. The hospital’s database was searched to determine whether the parents had visited the emergency department in the 12 months before their child’s referral to the RCCAN. Results Eight missed cases out of 120 cases were found. The reasons for not referring were as follows: forgetting to ask about children and assuming that it was not necessary to refer children if parents indicated that they were already receiving some form of family support. Discussion Barriers to identifying missing cases could be relatively easy to overcome. Regular training of emergency nurses and an automated alert in the electronic health record to prompt clinicians and emergency nurses may help prevent cases being missed in the future.