We investigated how nutrient addition affects the abundance, nutrient storage, and competition between Distichlis spicata and Salicornia bigelovii, two dominant species in salt pans of Northern Gulf of Mexico marshes. Namely, we compared fertilized and unfertilized plots in monospecific areas colonized respectively by D. spicata or S. bigelovii, and in a mixed area colonized by the two species. Nutrient addition generally increased the aboveground biomass and percent cover of the two species, and those increases were moderate to large in relation to the increases found for other marsh plant species. Nutrient addition also generally decreased the carbon:nitrogen and carbon:phosphorus ratios of aboveground and belowground tissues of the two species. Our results provide evidence that, under enhanced nutrient availability, D. spicata is a superior competitor over S. bigelovii in the mixed zone of the salt pan where the two species grow together. However, we did not detect large changes in biomass dominance by D. spicata following fertilization, possibly because the experiment only lasted 10 months. Our results suggest that nutrient addition, by increasing the structural complexity of the leaf canopy and the nutritional quality of plant tissues for first-order consumers, may enhance the value of salt pans as habitat for organisms