Passively Q-switched ceramic Nd3+:YAG lasers with ceramic Cr4+:YAG saturable absorbers are demonstrated. When the lasers are pumped by a 1-W cw laser diode, optical-optical efficiency as great as 22% is obtained with Cr4+:YAG of initial transmission ranging from 94% to 79%. The results are similar to those in their crystalline counterparts. The operation of Brewster's angle and the polarization state of the laser output are also investigated.