Resumo. The objective of this work was to evaluate different water regimes on initial growth and some physiological variables of physic nut ( Jatropha curcas L.) in dystrophic Haplustox. The experiment was carried under greenhouse conditions of the Embrapa Western Agriculture, located in Dourados, Mato Grosso do Sul State, Brazil. Treatments corresponded to water regimes of 20, 40, 60, 80 e 100% of the soil water retention capacity. The experimental design adopted was completely randomized with five treatments and five replicates. The evaluations of plants height, stem diameter and number of leaves were performed in six dates, while the variables stomatal conductance and photosynthetic rate were determined in two dates. At the end of experiment were evaluated the leaf area, dry mass of the leaves, petioles, stems and roots of all plants of physic nut. The water regimes of 60% and 80% of the soil water retention capacity provide the best responses to the physiological variables and of growth in the initial phase of physic nut. Available water contents in a dystrophic Haplustox, below of 60% and superiors the 80% of the soil water retention capacity induce signs of water stress in young plants of physic nut.