Objectives: The current study aimed to standardize the neuropsychological test of NEPSY on 3-4 years old children. Method: Statistical population of the study was 3-4 years old children in Isfahan city (Iran). The research sample consisted of 400 kindergarten children who were selected randomly with multiple-stage sampling method. The research instrument was the neuropsychological test of NEPSY. The data were analyzed using descriptive method for factor analysis and determining the validity and reliability. Results: The results of factor analysis gave the following five factors: executive functions/attention, language, sensory motor functions, visuo-spatial processing, and memory and learning. Totally, 51.13% of variance was explained. The reliability coefficient for the above factors was obtained as 0.64, 0.71, 0.78, 0.67 and 0.85, respectively (P<0.001). Conclusion:  NEPSY test can be an appropriate and valid instrument for early diagnosing neuropsychological deficits in 3-4 years old children.