The favourable scaffold for bone tissue engineering should be characterized, among others, by high mechanical strength and 3D open porosity, which guarantee biocompatibility and suitable environment for tissue regeneration. Numerical modeling could be used as a tool for preclinical evaluation and optimization of the scaffold. In fact, optimization of such complex structures like bone scaffolds is a great challenge for investigators. In the paper optimization of material application for particular fiber of scaffold fabricated by FDM was described. The objective of optimization is the best possible mechanical strength – degradation rate ratio. The used method of optimization was standard Genethic Algorithm, which is efficient method of discrete optimization, especially when solved problem is characterized by a great number of variables. In case of optimization of bone scaffold, number of variables is equal to number of fibers. Each of fibers could be made by different material (number of used materials is 5). The ultimate goal of study was to created optimal scaffold model for simulations of new bone formation.The numerical models of the scaffolds were generated using MSC/Patran. The generated mesh was optimized by SED criterium and finally consisted of about 270,000 finite elements. Results showed that, application of different material for particular fiber is very efficient method of controling the scaffold behaviour during healing process.