Color vision is one of the most important factors of human vision. Early detection of color vision malfunction in children is of utmost importance, allowing parents and teachers to take appropriate and timely measures for children’s future professional orientation. A cohort of 300 children aged 4–6 years (49–86 months) were examined by color vision testing and divided into three age groups of 4–5, 5–6 and > 6 years. Their ability to name the fundamental spectral colors and read Ishihara’s pseudoisochromatic plates was recorded. The results obtained are presented in tables and figures. Data analysis showed the youngest group of children to be unsuitable for such testing of color vision. Numerical data revealed considerable percentage deviations as compared to the older groups. In addition, a great difference between the girls and boys indicated psychomotor development to be much faster in girls of that age. Generally, data obtained by the distribution of the results for the two older age groups were consistent with those found in the literature; thus, the authors propose an early examination for the detection of inborn chromatopsia to be performed in preschool children, but not before the age of five. Ishihara’s pseudoisochromatic test can be useful in differentiating between dyschromatic and other children, but it is very difficult to implement for singling out dyschromates according to the protan or deutan type.