Thermoelectric and electrical properties of transparent p-type CuAlO2 thin films deposited by dc-sputtering method have been studied in detail. Postdeposition annealing in excess oxygen is a necessary precondition of obtaining enhanced p-type conduction in the films. The effect of postdeposition annealing time in excess oxygen on electrical and thermoelectric properties was studied. Thermoelectric measurements of the films, showed considerable high values of room-temperature Seebeck coefficients ranging from 230 to 120 muV K-1, for annealing times of 90 to 30 min, respectively. Natural layered-structure materials, having an effective two-dimensional carrier density, showed an enhanced thermoelectric figure-of-merit. CuAlO2, having a natural superlattice structure, showed very good thermoelectric properties, and it may become a good thermoelectric material for future applications. (C) 2004 Elsevier B.V. All rights reserved.