Concentrations of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) compounds were analyzed in sediment samples collected from twelve stations along the eastern seaboard of the Fulf of Thailand. The total butyltin (EBTs) concentrations ranged between <1 and 44.7 ng/g (wet wt). The overall concentration ranges found in the sediments were <1 -32.5 ng/g for MBT, <1-7.1 ng/g for DBT, and <1-12.2 ng/g for TBT, on a wet weight basis. MBT generally prevailed in most of the samples, suggesting the occurrence of old inputs of butyltin compounds in the area. Butyltin compounds were also measured in some marine gastropods, such as Nassarius sp. and Chicoreus capucinus, where EBTs concentrations were found to range between <1 to 238 ng/g (wet/wt). The level of butyltin compounds in gastropod in gastropod tissue samples tends to be related with that of the sediments and percentage of imposex incidence.