Fruits of columnar cacti are an important food resource from the arid lands of MeH xico. However, little is known about their nutritional value. In this paper, seeds of "ve species of columnar cacti from the Sonoran desert were studied to determine their protein and oil composition. The studied species were: Pachycereus pringlei, Pachycereus pecten-aboriginum, Carnegiea gigantea, Stenocereus thurberi and Stenocereus gummosus. Protein content varied from 20.3 to 22.0% among species. These proteins showed a high content of sulfur containing amino acids but were low in lysine. In vitro digestibility ranged from 77 to 86% among species and increased with the thermal treatment. Protein from P. pringlei was assessed in vivo and showed PER values of 2.8% and digestibility of 91.6%. Oil content ranged from 28.4 to 30.7% among species. Most oils showed a high degree of unsaturation. Linoleic (50}53%) and oleic (35}37%) acid were the most important fatty acids present in all oils. The results are compared with other studies on the seeds of columnar cacti. Future studies aimed at evaluating the nutritional value of the fruits are discussed.