The growth of unintentionally doped indium phosphide by low pressure metalorganic chemical vapor deposition (LPMOCVD) using triethlylindium and phosphine has been investigated by low temperature photoluminescence (PL). Pregrowth annealing was found to result in improved crystalline quality of the seed surface. The predominant acceptor impurity on the annealed substrate surface and in the initial epitaxial region (1200 A˚) was shown to be carbon. The major acceptor impurity in thicker epilayers further away from the substrate interface was determined to be Zn. Silicon was also identified from the PL spectra, though its concentration might be much smaller than that of zinc. No deep level impurities were observed in this material. Most important of all, the highly resolved exciton PL spectrum demonstrated that excellent quality InP comparable to the best material grown by vapor phase epitaxy could be grown by LPMOCVD without the need for phosphine cracking.