The objective of this study was to investigate the feasibility of using serum heart fatty acid-binding protein (H-FABP) concentrations as an early biomarker for doxorubicin-induced myocardial damage. Forty-four male rabbits were randomly divided into a control (8 rabbits) or one of four doxorubicin groups (8 rabbits in each group). Rabbits in the control group received saline, whereas rabbits in the doxorubicin group received 2 mg/kg doxorubicin weekly for 1-8 weeks. Rabbits in the doxorubicin groups received doxorubicin 2 mg/kg for one (Group 1, 8 rabbits), two (Group 2, 8 rabbits), four (Group 3, 9 rabbits), or eight (Group 4, 11 rabbits) weeks. Echocardiography was performed to measure left ventricular ejection fraction (LVEF), shortening fraction (FS), and E/A ratio. Cardiotoxicity scores were assessed by light microscopy using Billingham's method and also by electron microscopy. Serum H-FABP concentrations were quantified by a rabbit-specific enzyme-linked immunosorbent assay. Decreased LVEF, FS, and E/A ratio were detected in Group 4 (P < 0.05). Billingham cardiomyopathy scores of the rabbits in Group 3 were significantly higher (P < 0.05) than those of rabbits in the control group or Groups 1 or 2. Billingham cardiomyopathy scores in Group 4 were the highest of all groups (P < 0.05). Myocardial injury was demonstrable by electron microscopy in rabbits in Groups 2, 3, and 4. Compared with the control group, serum H-FABP concentrations increased only in Group 4 (P < 0.05). Serum H-FABP concentrations may not be a sensitive method for assessing early cardiotoxicity of doxorubicin.