OBJECTIVE: To determine the content of netilmicin sulfate in serum by a high performance liquid chromatography-indirect photometric determination (HPLC-IPD) method. METHOD: The chromatographic system consisted of Soheisorb C18 column and mobile phase of a solution of methyl alcohol-a buffer of phosphoric acid (pH=2.0) (20∶80), that contained 0.5 mmolL-1 of nicotinamide and 0.3 mmolL-1 of sodium seventhalkyl-sulphonate. The detected wave length was 268 nm. The serum simple of 4 patients was determined. RESULTS: The mean recovery of was 93.41% and detection limits was 50 μgL-1. CONCLUSION: The method is constant, sensitive, and has a good concentration. It is good for determination of netilmicin sulfate concentration in serum.