A simple, sensitive and reliable high performance liquid chromatography (HPLC) method has been developed and validated to simultaneous determination of albendazole metabolites: albendazole sulphoxide (ABZSO) and albendazole sulphone (ABZSO2) in plasma. The chromatographic separations were achieved on a reversed phase C18 column (250x4.6 mm, 5μm) using a mixture of acetonitrile/ammonium phosphate buffer (0.025M, pH=5), the flow a rate UV detection were set at 1.2 ml/min and 295 nm, respectively. The total run time for the method was within 18 min. The method was found to show a good linearity in the concentration range of 0.01 - 2 μg/ml for both analytes (ABZSO and ABZSO2) with a correlation coefficient of 0.998 and 0.999 for ABZSO and ABZSO2, respectively. The assay was accurate and reproducible with a quantification limit of 0.01μg/ml for ABZSO and ABZSO2. Intra-day coefficients of variation of ABZSO and ABZSO2 were 3.75 and 3.39 % respectively, while the recovery accuracy was between 81.39% for ABZSO and 81.66% for ABZSO2. This method appears to be robust and has been successfully applied to a pharmacokinetic study of albendazole in dogs.