Introduction: Performance of mountaineers, civil aircraft pilots, and of the personnel involved in many military operations in high mountains may rely on color discrimination at these moderate levels. The authors aimed at investigating the effects of moderate altitude (3000 m) exposure on color vision. Methods: Sixteen high school students, ages ranging between 14 and 17 yr, were enrolled in this study. Their color vision was examined with the Farnsworth-Munsell 100-Hue (FM-100 Hue) test at 1060 and 3000 m above the sea level and the total number of errors (all 4 sectors together) compared. Number of errors was also calculated for each of 4 sub-sectors and compared between these two altitudes. Results: There was a statistically significant increase in total number of errors (p = 0.001) as well as in number of errors in sector 1 (p = 0.007) and sector 3 (p = 0.013) at 3000 m when compared with 1060 m. Conclusions: Moderate altitude (3000 m) adversely affected the total number of errors on FM-100 Hue color vision testing of an acclimatized group of young individuals in a photopic environment and this deterioriation was significant in the blue-yellow range.