Based on Thailand national policy to expand rubber plantations in Northeastern and Northern regions, the performance information under drought conditions need to be developed for this specie. Carbon exchange rate and plant water status of two popular commercial clones (RRIM 600 and RRIT 251) under non-water stress and water stress conditions were studied on two year-old of rubber plants. Under non-water stress condition plants, differences of photosynthetic traits, nitrogen and water status between clones were found. According to water stress condition, drought treatments provoked a strong stomatal closure and a decrease in xylem pressure. During 7 days after irrigation was stopped, stomatal conductance (gs) was more substantially reduced for both clones and it closed to zero at 21 days. Minimum xylem pressure in the petiols (Ppetiole) for control plants varied between -0.7 and -0.8 MPa. At 28 days after the onset of the drought treatment, Ppetiole was reduced to -1.7 and -2 MPa for the RRIM 600 and RRIT 251 clones, respectively. The dependence of gs on Ppetiole was found for both clones. Maximum transpiration rate (Emax) was showed a constant value all experimental period time for control plant, while it was more substantially reduced after 10 days for stress plant. These results confirm the potential genotypic variability of some photosynthetic trait and water status under non-water stress conditions and stomatal behavior related with hydraulic properties during water stress in rubber tree.