Tributyltin is an important chemical in industrial production. Especially it is used in manufacturing of vinyl polymers (Batt, 2006) and as antifouling agents on the water contacting surfaces of aquatic vehicles (Boyer, 1989). However they possess various health hazards in food web and to humans. They produce health problems such as endocrine disruption, immune suppression (Krajnc et al, 1984) and oxidative stress (Mitra et al, 2013). In this study effect of tributyltin on erythrocyte fragility, antioxidant parameters and hematological parameters were studied. 28 days of oral administration of tributyltin chloride (5 mg/kg), vehicle for tributyltin (corn oil), omega 3 oil (250 mg/kg) and their concomitant use was conducted on male Wistar-albino rats weighing 200-250 grams (n=7 for each group). Rats were anaesthetised with a mixture of ketamine (50mg kg-1) and xylazine (4 mg kg-1, both i.p.) and blood was withdrawn into EDTA containing tubes. Erythrocyte fragility was measured as level of osmotic hemolysis due to increased distilled water content and read with a spectrophotometer at 546 nm. Hematological parameters (hemoglobin, hematocrit, red blood cell, white blood cell, platelet, lymphocyte, monocyte, neutrophil count, percentages of them and calculations such as mean corpuscular volume) were measured with an automated device for animal studies. Concentration of gluthation in blood was measured (Beutler et al, 1963). Superoxide dismutase was measured according to percent inhibition of formazan dye formation at 505 nm. Gluthation peroxidase was assayed by targettigs oxidation of gluthation by cumene hydroperoxide . Malondialdehyde which is an indicator of lipid peroxidation in erythrocytes was measured based on thiobarbituric acid reactivity. Results, which are all given as Mean±Standard Deviation, indicate significant increase in erythrocyte fragility due to vehicle used for dissolving tributyltin at 0.5% concentration (58%) compared to control (36%) and no additive effect of tributyltin was observed on fragility (54%). Tributyltin decreased level of an important antioxidant enzyme gluthation peroxidase (17.24±1.9) compared to control (23.97±2.76) (p<0.05) and concomitant omega 3 administration with tributyltin recovered this untoward result (24.6±5.22). Although insignificant, hematological findings of the study indicate a lymphocyte suppression in quantity in tributyltin group (4.90±1.10) compared to control (6.19±2.16). This effect was also ameliorated with omega 3 use (5.51±1.10). Results of this study suggest that consumption of omega 3 can at least partially recover some untoward physiological effects of tributyltin intake consumed from the same aquatic food source.