Butyltins (TBT, DBT, MBT) were measured in water and sediment samples collected from various locations in the Mandovi (ten stations) and Zuari (nine stations) estuaries, Goa, India, during November 2007. The total butyltin (TB) in water samples varied between approx. 12 and 73 and from 0.5 to 77 ng Sn l sup(-1), whereas for the sediments, it varied from approx. 15 to 118 and 6 to 119 ng Sn g sup(-1) dry weight for the Mandovi and the Zuari estuaries, respectively. The average TB concentration in the sediments from the Zuari estuary was higher as compared to the Mandovi estuary, whereas for the water samples, it was vice versa. For both the water and sediment samples, MBT was generally the most predominant butyltin in these two estuaries. This suggests that the butyltin contamination was not freshly derived. Fairly good relationships between the concentrations of TB and organic carbon in water and sediment samples of these estuaries implicate the importance of adsorption / desorption processes in controlling the levels of TB in these estuaries.