OBJECTIVE To observe the behavioral changes of rats after subchronic exposure to di-(2-ethyl hexyl) phthalate (DEHP). METHODS Twenty-four healthy male SD rats were randomized equally into 4 groups, namely the solvent control group (sesame oil) and 3 DEHP groups with daily intragastric administration of DEHP at the doses of 150, 450, and 1350 mg/kg for 28 days. The neurobehavioral changes of rats were evaluated by open-field test (OFT) and elevated plus-maze test (EPM), and the body weight and organ coefficients were measured. RESULTS The rats showed no significant differences in the performance in OFT or EPM before DEHP exposure. The body weight of the rats increased with the prolonged DEHP exposure, but no significant differences were found between the treatment groups and the control group (P>0.05). From the third week of exposure, the weekly food consumption and the food utilization rate showed significant differences between the treatment groups and the control group (P<0.05 and PP<0.01), and the liver and testis coefficients, but not the kidney coefficient, also differed significantly (PP<0.01, PP<0.01, and P>0.05). In OFT, the total distance of movement was the longest in high dose treatment group (PP<0.05 vs control group), and the durations of stay in the central area, but not the number of times of entry, differed significantly between the 3 treatment groups and the control group (PP<0.05 and P>0.05). In EPM test, however, the performances of the rats was all similar between the 4 groups (P>0.05). CONCLUSIONS DEHP can affect the locomotor activity and exploratory behavior of rats after short-term exposure, suggesting its possible hazard in human being.