The response of two faba bean lines (F84 and F85) to the high salinity, 300 and 400 meq of NaCI+CaC12 (v/v) is evaluated by the pro-line analysis. This marker of the resistance to the environmental stress is analysed in the young leaves, stems and roots aged 24 and 43 days that is to say on the 4th and 23rd days after the salt stress. The amount of proline differs according to the age of the plant, the organ, the line and the treatment. In the stems of F84, an inhibition of proline is revealed on the 4th day of the stress; on 23rd day, this amino acid decreases in the roots stressed. For F85, proline accumulates highly on 4th day in the leaves stressed and on 23rd day, this nitrogen compound is more abun­dant in all stressed plants.