During the past several years attempts have been made to grow thick epitaxial films of PbS, PbTe, PbSe, and their alloys with tin on alkali halide substrates. The thickest films which have been achieved using conventional evaporation techniques were limited to 10–15 μ m. We have developed a quasiequilibrium system which has yielded thick films of Pb1−xSnxTe ranging up to 328 μm. When combined with appropriate substrate preparations, this technique yields films having optical quality surfaces and good adherence to the substrate. In addition, the films may be easily removed from their substrates, intact and undistorted, by dissolving the substrates. Various electrical, optical, and thermal measurements on these thick films show that they are homogeneous. X-ray data indicate that the films are of high crystalline quality.