Fishery products are highly perishable foods. To increase their shelf-life is necessary to apply treatments that preserve the quality. The processes should ensure the safety of the product and does not alter the organoleptic and nutritional characteristics. To extend the shelf-life of fish products can be used extracts of rosemary (Rosmarinus officinalis). The rosemary extract contains diterpenes, flavones, and caffeic derivatives which have antioxidant activity of which the 90% of the activity is due to the carnosic acid and carnosol. Traditional preservation methods used for fish products do not guarantee the stopping of the oxidation of lipids. Salting and drying accelerate lipid peroxidation and the temperature reached by freezing (-18°C), do not stop the oxidation. The fish products can be treated with extracts of rosemary before being vacuum packed, or used in combination with other methods. This can be used to preserve the quality of the fish avoiding the use of chemical additives. Some of the rosemary extracts used in the food industry are deodorized, while others retain the aromas that can be enjoyable for a preparation of fish already flavored.