An electronic endoscope system, including a scope that outputs a plurality of types of color signals obtained by an imaging device and a processor for processing the signals outputted from the scope. A color conversion matrix in which each element data value is defined such that only a color involved in diagnosis is converted to desired color is stored in a memory of the scope or in a memory of the processor. The processor includes at least one multiplier that multiplies the plurality of types of color signals outputted from the scope by coefficients, each provided for each color signal, a coefficient setting means (microcomputers) for setting each element data of the color conversion matrix read out from the memory in the multiplier as the coefficients, and at least one adder that adds up signals outputted from the multiplier.
