A chemical study was conducted on the marine alga Ulva luctuca, collected during the summer of 1994 in La Paz, B.C.S. (Mexico). The results were as follows: crude protein, 10.7%; carbohydrates, 30.9%; ashes, 53.2%; crude fiber, 4.8%; in vitro digestibility, 64.6%; multienzymatic digestibility, 86.5%. Precipitation was detected in the qualitative analysis of the alkaloids. The minerals analyzed were: calcium (0.84%), iron (0.66%), phosphorous (0.14%) and chloride (9.8%). Ulva lactuca is found in great abundance in the area and it is concluded that, due to its chemical composition and high mineral content, it can be used as a mineral supplement for poultry.