The origin of Jatropha curcas L. is in Central America, probably Mexico, although it is also distributed in South America, Africa and Asia. In Mexico, it grows as nontoxic and toxic J. curcas genotypes. In this work, the protein quality including protein efficiency ratio (PER), net protein ratio (NPR) and true digestibility (TD) of nontoxic genotype defatted flour was assessed using Wistar rats. The probed diets contained flour (3), flour‐lysine, 1% (4), flour‐phytase, 500 FTU (5) and two control diets: nitrogen‐free (1) and casein (2). The rats were fed for 28 days. The PER (1.37, 1.77 and 1.61) and NPR (1.80, 2.29 and 2.12) obtained values for diets (3.4 and 5) were lower than those obtained for casein (2.07 and 2.46), respectively. No statistical differences were found in TD. PRACTICAL APPLICATIONS Jatropha curcas defatted flour may be used in the food industry for the development of diets for human and animal consumption. Besides achieving fortification of foods that are made from wheat, which has a low protein content, with the addition of Jatropha meal, these foods will improve the protein quality of many food products.