Monolithic integrated optoelectronic circuits, which incorporate electronic and optical devices on the same substrate, have the advantages of smaller size, and potentially higher reliability compared with conventional hybrid circuits. In addition, significant improvements in the speed and noise performance of communication systems can be realized. This paper reviews the various elements which constitute the integrated optoelectronic circuits (IOEC's) with emphasis on the structure of GaAlAs injection lasers. Several integrated circuits on GaAs substrates are described in detail. A view of optoelectronic circuits in other III-V compounds is presented.