This paper is on the short-term thermal scheduling (STTS) problem, particularly concerning the new competitive and environmentally constrained electricity supply industry. On the one hand, within the electricity market, STTS has evolved from a minimum-cost policy in state-owned monopolistic companies to a profit-based policy under market conditions. On the other hand, as a consequence of growing environmental concerns, an unprecedented change points to a scenario where it is necessary to take into account the constraints related to the environment. We propose a multiobjective optimization (MO) approach to solve the profit-based STTS problem with environmental concerns. Two case studies are considered: the IEEE 30-bus system and a 75-bus system. Finally, conclusions are duly drawn.