Abstract: A method of HPLC for the simultaneous determination of diuron and copper pyrithione in marine paint was proposed. The sample (0.020 0 g) was extracted ultrasonically for 10 min with ethyl acetate (10 mL). An aliquot of 1 mL of the supernatant was taken and after mixing with 1 mL of acetonitrile was separated on Agilent ZORBAX Eclipse XDB-C18 chromatographic column with mixtures of acetonitile and water with different mixing ratios as mobile phase in the gradient elution. DAD was used in detection. Linearity ranges of diuron and copper pyrithione were found between 0.15-800, 0.20-200 mg·L-1 respectively. Detection limits (3S/N) found were 8.0 mg·kg-1 for diuron and 12.0 mg·kg-1 for copper pyrithione. On the base of blank sample, test for recovery was made by standard addition method at 3 concentration levels, values of recovery found were in the range of 90.0%-95.0%, with RSD′s (n=6) in the range of 1.7%-3.4%.