The goal of this thesis was to develop a program able to solve steel frame optimization problems using a two-phase approach. This optimization problem consists of minimizing the weight of a steel frame ensuring that the solution found satisfies all the strength and stability criteria establish in Eurocode 3. The two-phase approach consists of first finding a continuous solution and after it, using this first solution to select the closest standardized profiles and find among them the optimum discrete solution. This optimization method was implemented using Python and checked with Ftool that all the structural calculations were correct. Two different formulations had been written following the same structure but with a big difference, the first one has only one design variable (h) and the second has 5 (h,b,tf,tw,r). As the first formulation has only one design variable, the correlation between h and all the other design variables needed to be found. To be able to approximate all the other variables it is necessary to know which profile family is each member of the frame, for this reason in the first formulation all columns are HEA profiles and beams IPE. However, in the second problem, all members can be from any of the I families. These two different formulations had been done to compare if the results obtained using all the design variables improve significantly and how much the computation time increased. This way, it was possible to compare if it was worth it to use all the variables. Moreover, three different optimization algorithms were used in the first phase to check which one was better.