This study determines the effects of phosphorus, applied in various doses (0-30-60-90-120 kg ha-1 ), on the seed yield, protein and amino acid content of the faba bean (Salkim, Filiz and Kitik). The study was conducted in the 2022 and 2023 growing seasons in the experimental field of the Faculty of Agriculture of Aydin Adnan Menderes University. The effect of different interactions of cultivar and phosphorus dose on the seed yield and on the levels of the amino acids aspartic acid, serine, alanine, arginine, threosine and histidine was found to be significant, as was the effect of the phosphorus dose on the protein ratio. The optimum values for the seed yield (2.14t ha-1 ) and protein (26.4%) were obtained when the phosphorus was applied at 60kg ha-1 . Among the cultivars, Kitik achieved a higher yield and protein ratio than the others. Arginine (1.056g/100g) and aspartic acid (1.125g/100g) were the amino acids found in the greatest quantities in the faba beans. However, while methionine (0.087g/100g) and cysteine (0.085g/100 g) were the essential amino acids present in the smallest quantities, the application of phosphorus increased the levels of these amino acids. As a result, the changes brought about in the yield, protein content and amino acid content of the faba bean cultivars by applying various doses of phosphorus were determined, revealing ways in which the nutritional value of the seeds might be enhanced.