Solid-phase microextraction (SPME) coupled to gas chromatography-mass spectrometry was applied to determine the antifouling biocides chlorothalonil, dichlofluanid, sea nine 211 and irgarol 1051 in marine sediments. Two experimental approaches were selected before the submission of the aqueous extracts to SPME prior to GC determination. The extraction of the biocides from the sediment samples was conducted using (a) water (containing 5%, v/v, acetone) and (b) acetone which was then diluted with water to give a 5% (v/v) content. The recommended procedures were found to be applicable for quantitative determination of the selected antifouling compounds in sediments with R.S.D.s below 17% and limits of detection ranging from 0.5 to 25 ng/g. The acetone/SPME procedure showed lower detection limits (0.5 to 6 ng/g) and R.S.D. values (< 11%) as well as better recoveries (73 to 92%), proving that it could be successfully performed for the determination of antifouling compounds in sediment analysis, even in samples with high organic matter content. Both optimized water/SPME and acetone/SPME procedures were applied to the analysis of antifouling compounds in marine sediments and compared with the conventional liquid-liquid extraction with subsequent clean up by solid-phase extraction.