A comparative analysis using different intelligent techniques has been carried out for the Economic Load Dispatch (ELD) problem considering line flow constraints for the regulated power system to ensure a practical, economical and secure generation schedule. The objective of this paper is to minimize the total production cost of the thermal power generation. Economic Load Dispatch (ELD) has been applied to obtain optimal fuel cost. Optimal Power Flow has been carried out to obtain ELD solutions with minimum operating cost satisfying both unit and network constraints. In this paper, various intelligent techniques such as Genetic Algorithm (GA), Evolutionary Programming (EP), Particle Swarm Optimization (PSO), and Differential Evolution (DE) have been applied to obtain ELD solutions. The proposed algorithm has been tested on two sample systems viz IEEE 30 bus system and a 15 unit system. The results obtained by the various intelligent techniques are compared. The solutions obtained are quite encouraging and useful in the economic environment. The algorithm and simulation are carried out using Matlab software. © 2008 IEEE.