This paper presents the modified ant colony optimization (MACO) based algorithm to find global optimum. Algorithm is based on that solution space of problem is restricted by the best solution of the previous iteration. Furthermore, the proposed algorithm is that variables of problem are optimized concurrently. This algorithm was tested on some standard test functions, and successful results were obtained. its performance was compared with the other algorithms, and observed to be better. (C) 2006 Elsevier B.V. All fights reserved.