Seeds of four bean varieties: BAT 104, Bayo Río Grande, Canario 107 and Jamapa were studied with the objective of characterize them by the analysis of protein content, L-tryptophan (L-trp) and available L-methionine (L-met) as well as technological qualities. Preliminar tests on the L-met and L-trp content were performed in soluble protein in aqueous extracts of NaCl, acetic acid and ethanol using microbiological and spectrometrical methods. Bayo Río Grande with the longest cooking time (98 minutes) showedthe largest proportion of coat weight (11.4); Bayo Río Grande, BAT 104 and Jamapa showed small seed size. BAT 104 was the variety in which the highest total protein content was found (27.3 %) while Bayo Río Grande had the lowest (23.3 %). The average content of both aminoacids from the four varieties was higher in the saline extracts (43 % L-met and 92 % L-trp). Therefore, the subsequent analysis were only performed on the saline extracts of the materials. The cultivars Bayo Río Grande and Canario 107 showed the highest amount of L-met and L-trp respectively.