Thermoelectric power generators are one of the promising clean energy resources with the cost effective operation despite the low device efficiency. Investigation into device efficiency improvement is necessary for the practical applications. Consequently, in the present study, a theoretical analysis of thermoelectric power generator is carried out and influence of thermoelectric leg geometry on the device efficiency and the power generation is formulated. The geometric configuration of the legs in the device is associated with the shape parameter and incorporated in the analysis. The influence of the shape parameter on the device efficiency and power generation is examined for various temperature and external load resistance ratios. It is found that increasing or decreasing of the shape parameter (mu) has a favorable effect on the device efficiency; however, the shape parameter (mu) has an adverse effect on the thermoelectric power generation. (C) 2012 Elsevier Ltd. All rights reserved.