In literature, economic dispatch problems are generally categorized as convex and nonconvex optimization problems. In this study, a solution is proposed for economic dispatch problem with valve point effect, which is one of the nonconvex optimization problems. For this reason the hybrid approach used for solution of this problem is formed as a combination of modified subgradient (MSG) and harmony search (HS) algorithms. This approach (MSG-HS) is applied in three different lossy test systems (Three machines 6-bus, IEEE 5-machines 14-bus, IEEE 6-machines 30-bus systems) solved with different methods in the literature. System losses are calculated by using B loss matrix. The resulting optimal solution values are compared with the solution values in the literature and the results are discussed. (C) 2011 Elsevier Ltd. All rights reserved.