In this paper, a new method for optimization of a wind-PV integrated hybrid system is presented. Based on deficiency of power supply probability (DPSP), relative excess power generated (REPG), unutilized energy probability (UEP), life cycle cost (LEC), levelized energy cost (LEC) and life cycle unit cost (LUC) of power generation with battery bank, the method addresses a specific location and employs an iterative scheme. A simulation software code has been developed to carryout the analysis for optimizing the size of the integrated system for a given location. Also, a case study using the software on the selection of optimal size of the integrated system for the site Pompuhar, Tamil Nadu state in India has been presented. (c) 2005 Elsevier Ltd. All rights reserved.