The objective of this paper was to verify the accumulation of free proline in leaves of beans (Phaseolus vulgaris L.) when subjected to water stress. Leaves samples were taken at 11 and 15 days after starting the water stress and 4 days after irrigation to estimate the proline accumulation. The results obtained showed differences among bean cultivars in the proline content and the capacity for accumulation of this aminoacid under 15 days of water stress. 'Jalo', 'Roseli', and 'Roxão Lustroso' were cultivars with the highest proline accumulation (> 7 mmol/g DW) whereas 'Moruna' and 'Curitibano Bairro das Palmeiras' were cultivars with the lowest proline content (< 3 mmol/g DW), after 15 days of water stress. The addition of water after 11 days of water stress showed proline content similar to the irrigated plants. The materials studied were classified as a function of their capacity for proline accumulation following 15 days of water stress. This classification represents differences in drought resistance if a higher proline contents is considered a measurement of the plant adaptation to the unfavorable condition.