Cellular beams became increasingly popular as an efficient structural form since their introduction. Their sophisticated design and profiling process provide greater flexibility in beam proportioning for strength, depth, size and location of circular holes. The main goal of manufacturing these beams is to increase the moment of inertia and section modulus, which results in greater strength and rigidity. Cellular beams are used as primary or secondary floor beams in order to achieve long spans and service integration. In this study, the design problem of cellular beams is formulated as optimum design problem. The minimum weight is taken as the design objective while the design constraints are implemented from The Steel Construction Institute Publication Number 100. The design methods adopted in this publication are consistent with BS5950 parts 1 and 3. The formulation of the design problem considering the limitations of the above mentioned turns out to be a discrete programming problem. Harmony search and particle swarm optimization methods are used for obtaining the solution of the design problem. The design algorithms based on these two techniques select the optimum UB section to be used in the production of a cellular beam subjected to a general loading, the optimum hole diameter and the optimum number of holes in the cellular beam. Furthermore, this selection is also carried out such that the design limitations are satisfied and the weight of the cellular beam is the minimum. A number of design examples are considered to demonstrate the efficiency of the algorithm presented. (C) 2010 Elsevier Ltd. All rights reserved.