This investigation was conducted to determine if the Ti-Al system gamma phase c/a ratio of unity for the crystal structure could be obtained. Data obtained are compared with reported data in which the c/a ratio of unity was predicted. The conclusions drawn are that the c/a ratio of unity can not be obtained as predicted, and that phases other than the gamma phase are present in alloys at which the prediction was made. Coincident with the lattice parameter determinations, a study was made of the presence of phases in the region of the Ti-Al-Zr ternary system between 45 and 55 atomic % Al. Two, and possible 3, new phases were observed, but their identification was not undertaken. The results of the phase investigation are given.