A dyschromatopsia deciding method and apparatus is provided. The apparatus includes an I/O interface configured to receive an input for a program, a memory configured to store the input for the program and a processing result of the input, and a processor configured to execute the program, wherein the processor is configured to provide first CAPTCHA information for distinguishing between a person and a machine together with second CAPTCHA information for deciding dyschromatopsia, receive first CAPTCHA input information corresponding to the first CAPTCHA information and second CAPTCHA input information corresponding to the second CAPTCHA information together with authentication information, authenticate a user based on the first CAPTCHA input information, decide dyschromatopsia of the user based on the second CAPTCHA input information, and store a decision result of the dyschromatopsia in response to a decision that the user has the dyschromatopsia.