In this study, the diets of different ratios (0 mg/kg, 30 mg/kg, 70 mg/kg β-carotene) of rainbow trout fillets coloured with β-carotene were storage of -18 °C for 6 monts period and monthly changes in the amount of β-carotene and lipid peroxidation were investigated. The amount of β-carotene was determined with spectrofotometer while the level of lipid peroxidation was determined by HPLC. The maximum coloration at the end of feeding was observed in 70 mg/kg β-carotene group. However, significant (p<0.05) colour losses were observed in this group during storage period it was observed that from the second month 70 mg/kg β-carotene has not got an important effect on lipid peroxidation level (p>0.05).