A simple screening method for the determination of toluene-extractable organotin compounds in water samples was developed. Organotins [tributyl tin (TBT), triphenyltin (TPhT) and dibutyl tin (DBT)] were extracted from 2 l of water sample with 10 mL of toluene in the presence of 2.5% (v/v) CH3COOH and 1.2% (w/w) NaCl. Aliquots of 240 µl of the toluene extracts were subjected to electrothermal atomic absorption spectrometry, utilizing the hot injection technique (injection temperature 120 °C) and chemical modification. Under these conditions, an enrichment factor of approximately 2000 was achieved. A comparative study of chemical modifiers was performed. Ten metals and mixtures of them were tested and the best results were obtained with 5 µg of Re. The characteristic mass was 90 pg and the instrumental limit of detection was 0.8 µg l−1 (as Sn), for all compounds tested. The overall limit of detection of the method was 2 ng l−1 (as Sn) for an injection aliquot of 240 µl. Quantitative recoveries were obtained for TBT and TPhT, whereas the DBT recovery was 70%. Addition of 0.5% (w/v) of tropolone in the extraction media resulted in 100% recovery of all organotins tested (TBT, DBT, monobutyl tin and TPhT), whereas, at the same time, inorganic tin was practically not recovered at 100-fold excess. The developed methodology was applied to fresh (lake) and marine waters of Greece and levels between < 2 and 223 ng l−1 were determined. Copyright © 2007 John Wiley & Sons, Ltd.