Chemical and microbial quality changes of freshwater crayfish (Astacus leptodactylus) tail fillet were studded during storage at freezing temperature. Samples were packaged and stored in-18 C in the freezer after fishing, preparation and peeling in the presence of air. Quality and microbial tests were performed on frozen fillets in time zero and once every month for 6 months with one treatment including three replicates for each test period. The results showed that at the end of six-months storage in freezer, the values (Mean±SE) of thiobarbituric acid (TBARS), peroxide value (PV) and total volatile nitrogenous bases (TVB-N) had reached from 0.05±0.005 to 1.45±0.25 mg, malondialdehyde/kg; 0 to 2.2±0.30 meqO2 kg/fish fat and 11.25±. 05 to 26.6±1.40 mg per 100 g of meat, respectively. These values were within the acceptable range for use in spite of exesting significant difference with each other (p< 0.05). pH value had no significant changes (p> 0.05) until the end of fifth months (6.2±0.25), but this value had a significant increase (6.57±0.55) after the sixth month (p< 0.05). At the same time, Total viable of bacteria (TVC) and psychrotropic bacteria (PTC) were reached from 3.49±0.01 to 6.86±0.08 log CFU/g and from 1±0.0 to 6.75±0.25 log CFU/g., respectively. Comparison of within group parameters during test period showed significant difference with each other (p< 0.05) but from the sixth month psychrotropic bacteria were on the verge of taking the risk for human consumption.