Abstract In this work the cyanide contamination was investigated in seawater, fish and mussel in Turkish coasts following the cyanide accident in Baia gold mines in Feb. 2000. The determination of cyanide was conducted according to Csikai and Barnard (1983) method slightly modified by us. Seawater sample was analysed after lyophilization or after addition of NaOH directly. Fish and mussel samples were extracted with water then analysed. The cyanide amount varied 0.13-3,01 µg/L in the Black Sea (K1,K2,K3), 0.11-0.34-µg/L in Igneada, 0.25-1.56µg/L in Kilyos and Rumeli Feneri and 0.09-1.74 µg/L in Istanbul Strait. The highest, levels of cyanide found in seawater of Turkish coasts is lower than the specified regulation limit of 5 µg/L. The cyanide was found in talbot 0.0052µg/g collected from Rumanian and. 0.032µg/g from Igneada coasts, 0.0093µg/g in gray mullet, 0.017µg/g in surmullet, 0.0072 µg/g in small blue fish , 0.00µg/g in silversid and 0.013 µg/g in flesh and 0.054µg/g in gut in common braetn (Aegean Sea), in mussel. 0.028 µg/g collected from Garipce, 0.056µg/g in Rumeli Feneri. The amounts of cyanide in fish and mussel are considered negligeable to be toxic for human consumption. This is first record on cyanide analysis in Turkish coasts.