The aim of this thesis is to investigate the influence of infill percentage and layer thickness on the tensile strength of test specimens made by the 3D printing process, with and without an adhesion layer, and to develop regression models for predicting tensile strength values. Factorial experimental design at two levels with three repetitions was applied. The input variables, which were varied at two levels, are infill percentage (20% and 50%) and layer thickness (0.1 mm and 0.2 mm), while the output variable is tensile strength. The experimental data were statistically analyzed using the analysis of variance method. For samples with an adhesion layer, it was determined that the infill percentage, layer thickness, and their interaction have a significant impact on tensile strength. For samples without an adhesion layer, it was found that the infill percentage and layer thickness have a significant impact on tensile strength, while their interaction is not significant. For both types of test specimens, regression models with high coefficients of determination R2 were obtained. The impact of the adhesion layer on tensile strength was also examined. By applying the method of hypothesis testing of the equality of arithmetic means, it was determined that there is no significant difference in the tensile strength values of samples with and without an adhesion layer. Hypothesis testing was conducted using the MS Excel software, while the analysis of variance and regression modeling were conducted using MS Excel, R, MATLAB, and Stat-Ease 360 software