Changes of free amino acid contents, proteolytic activity, and TBARS values in the vacuum-packed breast muscles of turkey stored at 1oC for 19 days were studied. Eighteen free amino acids were identified. Their total content after 1 day of storage was 171.36 mg/100 g tissue, proteolytic activity was 48.29 UH/g tissue, and TBARS values reached 0.66 mg MA/kg tissue. After 11 days, the contents of free amino acids and proteolytic activity significantly increased (by ca. 52% and 25%, respectively) whereas TBARS values decreased (by ca. 33%). After 19 days of storage the contents of free amino acids and TBARS values increased (by ca. 116% and 15%, respectively), whereas the proteolytic activity did not significantly differ from a control sample. While storing turkey breast muscles, a continuous increase in the concentrations of all detected free amino acids was observed except for Arg and Trp which were stable over the entire experimental period and for Tyr whose concentration increased significantly already after 4 days of storage and remained at this level throughout the storage period. The contents of free Asp, Asn, Gly, Thr, Ala, Val, Met, Phe, Ile, Leu, Lys, Pro and the percentage contents of free Asp, Ala, Val, Met, Phe, Ile, Leu, Lys could be regarded as indicators of storage time or spoilage.