<p>The use of composite steel and concrete systems in floors has grown over the past decades, typically with full web profiles, despite other beam topology alternatives such as cellular and tubular truss beams. The present study aims to provide a comparative analysis of the optimization of composite floor systems consisting of different beam topologies: open-web truss beams, truss beams with concrete-filled upper chords, and cellular beams. The objective functions adopted were the minimization of costs and the minimization of CO₂ emissions from the materials used on the floor, considered separately. The optimization problem was subject to constraints based on the guidelines for the design of steel structures and composite steel–concrete structures as prescribed by Brazilian standards. The solution to the optimization problem was obtained using Particle Swarm Optimization. A comparative analysis with full web floor systems and an analysis of the solutions obtained for the different topologies was carried out. The results indicate that, from both a cost perspective and an environmental perspective, floor systems composed of trusses and cellular beams provided better results than the full web floor system, with trusses featuring concrete-filled chords delivering the best solutions with concrete fillings having strengths above 25&#xa0;MPa.</p>