Passive surveillance using ICD codes for hospital discharges has been used to estimate the incidence of abusive head trauma (AHT) utilizing ICD-9-CM, but not ICD-10, codes. There have been no incidence estimates of AHT in Canada where ICD-10 codes have been used since 2002. The Discharge Abstract Database from the Canadian Institute of Health Information (CIHI) for 2002-2007 was used for analyses conducted in 2011. A case was defined by code combinations that indexed injury specificity (narrow or broad) and degree of certainty (presumptive or probable) that the injury was inflicted. Estimated incidences for the populations at risk in those aged