The physical basis of sputter-ion pumps (SIP) is the occurrence of several parallel processes. The specific features of SIP’s are determined mainly by the gas discharge, the sputtering of the cathode plates, and the implantation of fast gaseous particles in the metallic matrix. The model constructed in the one-particle approximation for a discharge operating under the first discharge regime is in good agreement with the experimental data. In the case of the dynamic forms of a discharge, the electronic current incident to the cathode and the secondary-emission electronic current are close in value. The pumping speed of an SIP is proportional in a first approximation to the discharge intensity. The influence of the ionic component on the sorption rate is comparatively weak: several hydrogen atoms are sorbed for each electron which has passed into the external circuit.