Study of methodologies for contact pressure calculation in integrated raceways bearings for aeronautical gearbox. More and more designers use advanced calculation methodologies for the optimisation of mechanical part performance. This is even truer in the aeronautic industry, where the power weight ratio must be as low as possible. Some CAD softwares (CATIA, SOLIDWORKS, PRO ENGINEER, etc.) provide the possibility to do complex computation. However these kinds of tools aren't currently able to easily estimate the contact pressure between two parts. This paper deals with the various methodologies usable in a CAD environment for the calculation of contact pressures in integrated raceways bearings for aeronautic gearbox. These methodologies may be analytical (Hertz theory), numerical (F.E.M.) or hybrid. They are analyzed and compared according to their precision, calculation time and readiness to be integrated in the industrial design process. An optimum contact pressure calculation methodology will be presented based upon the results of this analysis.