We discuss approaches to achieving large scale InP-based optoelectronic integrated circuits (OEICs) and photonic integrated circuits (PICs). During the past several years, significant advances have been made in improving materials and device quality of InP-based materials such as InGaAs(P) for use in long wavelength communications systems and networks. Hence, we are currently on the threshold of realizing large scale (greater than 500 device) OEICs from which will emerge a new generation of optoelectronic systems and applications, in analogy to what was achieved in the 1970s with the advent of Si-based electronic LSI. What remains to be demonstrated to bring this vision to practical reality is the demonstration of 'platform' integration technologies where devices and circuits custom-designed for a wide range of applications can be realized using a common (and simple) epitaxial materials structure and fabrication process. For the last several years, we have developed such platform technologies, with our latest success being the demonstration of a 16 by 16 InGaAs/InP imaging array consisting of 272 field effect transistors and 256 p-i-n detectors. Other devices which have been demonstrated using this technology have been very high sensitivity switched photodiode receivers, and coherent optical receivers. The transmitter technology consists of a modified twin waveguide structure which allows for fabrication tolerant fabrication of photonic integrated circuits employing any combination of lasers, optical amplifiers, modulators and waveguides. The extremely high yield and simplicity of processing of such InP-based LSI circuits suggests that the scale of optoelectronic integration in this important materials system has reached a new, and highly useful level of sophistication.