[tore Steel Ltd. is one of the largest spring-steel producers in Europe. [tore Steel makes more than 1400 steel grades of different chemical composition. Among them is 16MnCrS5 steel. It is generally used for the fabrication of case-hardened machine parts for various applications (e.g., bars, rods, plates, strips, forgings), where a combination of wear resistance, toughness and dynamic strength is essential. These properties can be easily correlated with tensile strength, which depends on the chemical composition and heat treatment after rolling. In addition, the elongation should be taken into account. In the paper, modeling of tensile strength and elongation with genetic programming is presented and compared with linear regression modeling. The chemical composition data (content of C, Mn, S and Cr) and the heat-treatment regime data (GKZ or BG annealing) were used for modeling. The modeling results show that a higher tensile strength with improved elongation were achieved. Keywords: 16MnCrS5, tensile strength, elongation, modeling, genetic programming, linear regression [tore Steel je najve~ji proizvajalec vzmetnega jekla v Evropi. [tore Steel izdeluje ve~kot 1400 razli~nih kvalitet jekla z razli~nimi kemijskimi sestavami. Med njmi tudi 16MnCrS5, ki spada v skupino jekel za cementacijo, ki so namenjena za strojno obdelavo razli~nih delov (npr. palic, plo{~, trakov, odkovkov), kjer se zahteva kombinacija obrabne odpornosti,`ilavosti ter trajnonihajne trdnosti. Le-te lastnosti lahko povezujemo z natezno trdnostjo, ki je odvisna predvsem od kemi~ne sestave in toplotne obdelave po valjanju. Prav tako je pomemben raztezek. V~lanku je predstavljeno modeliranje natezne trdnosti in raztezka s pomo~jo genetskega modeliranja in linearne regresije. Za modeliranje smo uporabili vsebnosti kemijskih elementov (C, Mn, S in Cr) ter na~in toplotne obdelave (GKZ ali BG). Glede na rezultate smo pove~ali natezno trdnost pri izbolj{anem raztezku.