Aims: This registry-based study examined differences according to socio-economic factors in the incidence of unintentional childhood injuries involving main injury types. Methods: All children aged 0-15 years living in the municipality of Odense were followed from January 1 2006 to December 31 2010 (n=176,585). Injury outcome (n=27,745) was defined as visits to the local emergency department. Cohort data were transferred to Statistics Denmark and linked with socio-economic registry data based on unique personal identification numbers. Results: Children aged 10-15 years were at the highest risk for any injury (incidence rate ratio (IRR)=1.14), traffic injury (IRR=5.89) and sports injury (IRR=49.58) compared to children aged 0-4 years. Girls were at lower risk for any injury (IRR=0.85) and higher risk for sports injury (IRR=1.11) and home injuries (IRR=1.12) compared to boys. Children of parents with the lowest household income were at the highest risk for any injury (IRR=1.19) and traffic injury (IRR=2.16) compared to children of parents with the highest group. Children of parents with primary education were at the highest risk of any injury (IRR=1.22) and the lowest risk of traffic injury (IRR=0.80) and sports injury (IRR=0.75) compared to children of parents with tertiary education. Immigrants and descendants were at lower risk for any injury (IRR=0.75 and 0.79, respectively) and sports injury (IRR=0.81 and 0.68, respectively) compared to Danish children. Conclusions: Injury risk varied with socio-economic factors in a Danish municipal setting. The effect varied between specific injury types. Social and ethnic background is important in establishing targeted preventive efforts, but some aspects of selection bias may occur.