The objective of the present research was to evaluate the response of five local populations of Medicago truncatula, collected from different sites of Djelfa (Algerian central steppe), to water stress. Two water levels were applied during experiment: normal irrigation treatment (control) and severe stress treatment (20% of pot capacity). At the beginning of the flowering stage, the following traits were measured: Stem length which has the first flower (SL), aerial biomass weight (ABW), root weight (RW), number of nodules (NN) and nodule weight (NW). Drought response index (DRI) was calculated. Analysis of variance showed significant variation among populations and between treatments for the measured traits. Significant differences between DRI values of aerial biomass weight, number of nodules and weight nodule were found too. In general, all measured characters were affected by water stress. The Reductions were more significant for all traits. The highest effect was observed for nodulation traits (number and weight of nodules). Based on DRI values, population from Mliliha region (Algeria) recorded the highest DRI values for plant growth and nodulation traits. This population seems to be drought tolerant and can to be used as parental material in Medicago species breeding program for drought tolerant.