The freezing of fish at (-18°C) in the freezer compartment of a domestic refrigerator for 2, 4, 6 and 8 weeks influenced the biochemical composition and mineral contents of the muscles. The chemical analysis of the muscles of the studied fish recorded high values (% dry weight) of protein, fat and ash contents and moisture for the fresh samples and there was a significant (P>0.05) decrease at the end of the eight weeks of freezing fish. The relationship between the four components of fresh and frozen Tilapia muscles was detected. There was only a significant (P>0.05) relationship between protein and fat contents (0.999) and between moisture and ash contents (0.998) after the 8 weeks of freezing, as for the mineral content of the frozen fish. The maximum values recorded throughout the freezing period were after 2 weeks of freezing (Cu, Ca, K, and Zn); after 4 weeks (P ,Na and K) and after 8 weeks (Mg, Fe and Na). In conclusion, the present results determinate the quality changes during storage period (8 weeks) and how long fish muscle can be stored without any deterioration in a domestic refrigerator.