Abstract : EURISOL DS (Europe Isotope Separation On-Line Design Study) project is the European common effort in planning a next generation RIB factory able to deliver secondary beams up to 1013 pps at energies up to 150 MeV u-1. The proposed schematic layout of the facility is based on four target stations, three direct targets of 100 kW of beam power and one multi-MW target two stages assembly. Being produced via spallation the RIBs produced in the direct targets are mainly proton rich. While in the multi-MW target high intensity RIBs of neutron rich isotopes are produced by fission in actinide targets placed in the fast neutron spectrum given by a liquid metal spallation source. The purpose of this paper is to summarize the work carried out within Task 11 “Beam Intensity Calculations” with special emphasis to the estimation of the in-target yield intensities produced in the various target configurations. Benchmark studies were performed initially in order to verify the accurate description of the spallation models used by the MCNPX2.5.0 code and to choose the best options to be used for the present work requirements. The predictions of the code tested against measured data are presented. Several calculations using MCNPX2.5.0 combined with the evolution code CINDER'90 were carried out to assess the performance of the direct targets. A complex analysis was performed to study the in-target production RIB intensities varying with various parameters: target dimensions, materials and incident proton beam energies. The optimized configurations for the targets together with the corresponding quantitative estimates of the production rates for all interested nuclei resulted from this investigation are discussed.