The effects of packing in oil and under vacuum on sensory, chemical and microbiological changes in marinated rainbow trout stored at chill temperatures (+4 +/- 1 degrees C) were studied. The quality assessment of marinated trout stored in oil and under vacuum was performed by monitoring sensory quality, total volatile basic nitrogen (TVB-N), peroxide value (PV) and thiobarbituric acid (TBA), psychrotrophic bacteria count and mesophilic bacteria count during storage. The observed organoleptic shelf-life of rainbow trout was found to be 105 days in oil and 90 days in vacuum packed samples. At the beginning of storage, the TVB-N value was 6.78 mg/100 g for marinated trout packed under oil and 7.35 mg/100 g for the vacuum packed samples. The TVB-N values increased to 12.08 mg/100 g and 11.98 mg/100 g by the end of the storage period for marinated rainbow trout packed in vacuum and in oil, respectively. No significant differences (p > 0.05) between the two groups of samples were found in TVB-N concentrations during the storage period. The fat degradation pattern (peroxide value and thiobarbituric acid content) was found to be similar for all storage conditions, showing a continuous increase reaching critical levels after ca. 60 days of storage for both packing types. Psychrotrophic bacteria count and mesophilic bacteria count of marinated trout were < 10 log CFU/g, throughout the storage period. The results of this study indicate that the shelf-life of marinated rainbow trout stored in cold storage (+4 degrees C), as determined by overall acceptability sensory scores, is 105 days for oil and 90 days for vacuum packaged samples.