An optimization analysis for an irreversible heat engine has been carried out based on a new thermoeconomic optimization criterion. The thermoeconomical objective function has been taken as the power output per unit total cost. In the analysis, the irreversibility effects due to heat transfer across finite temperature differences, the heat leak loss between the external heat reservoirs and internal dissipation of the working fluid are taken into account. The maximum of the objective function and the corresponding optimal conditions has been derived analytically. The effects of technical and economical parameters on the global and optimal performances have been investigated. © 2003 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.