Volume self-diffusion in high-purity (<1 ppm absolute total impurities) single-crystal tellurium has been determined between 300 and 400°C using Te127m as the tracer. Along , the data can be represented by D=1.30×102exp[(-1.75+/-0.05 eV)kT] cm2/sec, whereas D=3.91×104exp[(-2.03+/-0.10 eV)kT] cm2/sec represents the data along all the atomically equivalent directions perpendicular to . Above (300+/-7)°C, the self-diffusivity is higher perpendicular to the c axis than along . At lower temperatures, aluminum has been shown to increase, and iodine to decrease, the self-diffusion coefficient of tellurium along both the principal crystallographic directions. The vacancy-formation energy is estimated to be about 1 eV.