The objective of this work was to evaluate the morph ological variability of the yellow snapper Lutjanus argentiventris and the red snapper, Lutjanus colorado, in its natural environment in the Gulf of California México. Blood biochemistry and morph ological analysis were determined during the spring and autumn of 2016, in the San Ignacio-Navachiste-Macapule lagoon system, Sinaloa and each of them, 1.5 ml of blood was extracted to obtain the following biochemical parameters: proteins, cholesterol, triglycerides and glucose. Likewise, morphological tales such as hepatosomatic index, condition factor, gastr ic replenishment index and gonadsomatic index will be analyzed. In the evaluation of the blood chemistry reference values, no specific differences are observed between the species with respect to morphological indices, total proteins, triglycerides, cholesterol, but there are specific differences (P <0.05) in glucose in both species.