OBJECTIVE: To study the relationship between insulin resistance and myocardial injury in children with critical diseases in light of the fact that such children usually suffer from noticeable insulin resistance and myocardial injury. METHODS: Sixty-three children with critical diseases who were admitted between March 2010 and June 2011 were enrolled to comprise a case group. Fasting blood glucose, serum insulin, myocardial enzyme, and troponin I (CTnI) levels were measured. The insulin resistance index (HOMA-IR) was calculated. The children were classified into two groups: insulin resistance (HOMA-IR>1.0; n=30) and non-insulin resistance (HOMA-IR≤1.0; n=33). Thirty healthy children served as the control group. RESULTS: HOMA-IR, lactate dehydrogenase (LDH), aspartate aminotransferaseaspartate transaminase (AST), creatine kinase (CK), isoenzymes of creating kinase (CK-MB), α-hydroxybuty rate dehydrogenase (α-HBDH) and CTnI in the insulin resistance group were higher than those in the non-insulin resistance and the control groups (all P<0.05). The non-insulin resistance group also showed obviously higher levels in terms of LDH, AST, CK, CK-MB, α-HBDH, and CTnI than the control group (P<0.05). In the insulin resistance group, there exists a positive correlation between HOMA-IR and such indicators as LDH, CK, CK-MB, AST, α-HBDH and CTnI (r=0.697, 0.739, 0.781, 0.642, 0.381, 0.792 respectively; all P<0.05). CONCLUSIONS: Insulin resistance makes myocardial injury more serious; HOMA-IR can serve as a forecast indicator for the degree of myocardial injury.