Room-temperature optical pumped lasing emission in the red, green, and blue has been obtained from ZnCdMgSe/ZnCdSe quantum well (QW) laser structures grown on InP substrates. The structures are nearly identical, except for variations in the thickness and/or composition of the QW layer. No other single set of semiconductor materials has been demonstrated whose structures are pseudomorphic on one single substrate, and produces light emitters throughout the entire visible range. Our results demonstrate the potential for these materials as integrated full color display devices. © 1998 American Institute of Physics.