This article compared the efficiency of the mass screening test with projected color slides in detecting color-blindness with the authentic classic method of Ishihara. The study was conducted in a randomly selected lecture room with 104 students aged between 19-25 years (median 21). Using Ishihara projected slides, performed mass screening test. Re-testing was done individually with printed Ishihara plates. Six male and one female with color-blindness were detected. The frequency of color-blindness was 13.6% among males, with a total incidence of 6.7%. The results of two testing methods were compared statistically. Sensitivities and specificities of both tests were 100%. Using projected slides of Ishihara plates instead of the authentic method is an effective and timesaving method for detecting color-blindness. This method can be suggested as a mass-screening test and might be beneficial in detecting color-blindness in large populations such as students, soldiers, and so on.