Abstract. In this paper seamless tubes hot manufacturing calibration rolling is studied by means of a finite element model, to improve product quality and process performance. Based on real data provided by an industrial partner, Tubos Reunidos Group, a finite element model of the process has been created and validated for the thermo-mechanical analysis of the process. The model has been used for the study of the wall thickness evolution and peripherical distribution during process, the eccentricity and the polygonization effects. Results show that the tube velocity in the process is one of the factors affecting wall thickness eccentricity, due to mass flow conservation. Regarding polygonization and eccentricity effect it has been found that both effects increase in the rolling stands with higher reduction ratio, and are corrected afterwards. These effects are mainly due to the ovality of the rolls. However, the effect the different sliding velocity along roll perimeter has implications in the local deformation of the material in contact with the roll, causing local compressive stress areas in addition to the predominant tension areas.