We report a large increase in the thermoelectric properties of n-type lead telluride compounds synthesized by applying pressure tuning and temperature tuning simultaneously. The value of the thermoelectric figure of merit, ZT for PbTe measured at ambient temperature and pressure, 0.87, has been achieved. This value is nearly 20 times larger than that of PbTe synthesized at the ambient pressure, and approximately equal to that of Bi2Te3. It is suggested that this method has potential application in obtaining good quality thermoelectric materials. (C) 2002 Elsevier Science B.V. All rights reserved.