In this study, microbiological and chemical changes in frozen crayfish samples what stored at - 4ºC, -18 ºC and -35 ºC for 20 weeks, are investigated. Total number ol microorganisms were determined at three different incubation temperatures [5. 20 and 35ºC) and 1^st, 2^nd, 4^th, 8^th, 16^thh and 20^th weeks of storing period. It is determined that the total number of microorganisms are higher in samples stored at - 4 ºC then the ones stored at -18;C and -35"C. Staphylococcus-Micrococcus numbers increased up to 8th week in the sample stored - 4ºC and until end of storing period in the samples stored at -18 ºC and -35ºC. Total numbers of Coliform group microorganisms Increased in all the series and reached to the maximum at 20^th week. Any yeast and mould microorganisms were not observed in any of the samples during storing period. TVB-N amounts increased in samples stored - 4ºC up to 4^th week and as parallel to the other series later the rate ol increase was faster and reached to 58.52 mg/100 g at the end ol storing period. In the samples stored -18:C and -35 ºC this value varied between 2.8016 66 during storing period. The pH values showed a slow increase at the first weeks and fast increase in the following weeks. It is concluded that frozen crayfishes can be stored at -18 and -35ºC for 20 weeks without any decomposition. In the samples stored at -4 ºC numbers of microorganisms and some chemical values fast reach to the levels undesired and over the standards.