GSI-SIS18. We present the analysis of the inclusive K0 production in p+p and p+Nb collisions measured with the HADES detector in 2007 and 2008 respectively. The collisions take place at a beam kinetic energy of 3.5 GeV. The production cross section of K0 in p+p and p+Nb collisions are presented. ; Other ; The K0 production cross section in P P collisions.