Montia fontana L. is an aquatic plant traditionally consumed in the Centre and West of the Iberian Peninsula, where it is one of the most highly valued wild vegetables. The aim of this work wasto evaluate both the natural yield and nutritional value of this scarcely known plant. Two wild populations, from two different sites of Central Spain, were sampled during three consecutive years. Plant production was estimated by two parameters: production per unit of surface and plant percentage cover in the selected site. Nutritional analyses included proximate compositionand total energy, mineral macro and microelements, vitamin C, and organic acids.Mean yield at the growing areas was 2.64 kg/m2, though significant differences among sites and years were found. There is a positive correlation between production and accumulated rainfall from the beginning of the year till the collecting dates. The percentage cover of the species in the potential growing area was 8.25%, without significant differences among sites and years. Therefore, the wild populations of the species can reach a total mean production of 2138 kg/ha in this Spanish region.This is the first report of a global nutrient composition for Montia fontana. After moisture, the major constituent was fibre (4.44 %), much higher than many cultivated vegetables. Also appreciableamounts of vitamin C (34 mg/ 100g) and Mn (1.07 mg/100 g) have been found. Due to its high lipid content (1.94 %) this wild vegetable could be regarded as one of the richest source of omega-3 fatty acids among the leafy vegetables. This species can be considered an interesting wild resource for being included in the diet. More research is needed about its potential for being cultivated, different culture systems and selection of accessions with lower oxalate content.