Chub mackerel fillets were dipped in different concentrations of potassium sorbate, packaged under vacuum and stored at + 4 +/- 1 degreesC for 12 days. The microbiological and chemical changes (pH, TVB-N and TMA-N) of the samples were examined. Sensory evaluations were also performed. Untreated samples were stored under the same conditions and evaluated as the control group. Treated fillets had a lower microbial load and their chemical and sensorical parameters shomed smaller changes when compared with the control group. Submerging into potassium sorbate prolongs storage quality without any quality changes for 9 days.