Alkylphenol epoxylates (APE) are ubiquitous environmental polutants used as non-ionic surfectants in detergents, pesticides, herbicides, painta, cosmetics and plasticware. Biological degradation products of APEs namely nonylphenol (NP), octlyphenol (OP) and butylphenol (BP), which are found in water systems, are known as endocrine distrupters. In this study, alkylphenols are extracted from water samples and sediments, and also fish tissue collected from the stations along Sakarya and Degirmenderesi Rivers. Metanol extraction is applied for better resolution and the quantity of the pollutants are determined by isocratic and normal phase HPLC. Aps are not detected in water samples collected both from Sakarya and Degirmenderesi Rivers. However, NP (4,45 ug /g) and BP (1,68 ug /g) are detected in sediment samples collected at one of the stations of Degirmenderesi, and BP (3,15 ug /g) is found in sediment samples taken from one of the sites of Sakarya River. Nevertheless, NP and alkylphenol like chemical are detected in the tissue extracts of of almost all fish samples collected from all stations. NP treatment of rainbow trout under laboratory conditions results in the bioaccumulation in the tissues and histopathological abnormalities in liver tissue, and changes in glutathione S-transferase activities. The effects of NP treatment is also examined by FTIR at the molecular level. The increase in the vitellogenin amount in liver as determined by immunologic methods indicates the estrogenic behaviour of APEs.