This study is concerned with stimulation of various subcortical loci as a means of attenuating the aversive properties of concurrent painful stimuli applied peripherally. The medial forebrain bundle (situated in lateral hypothalamus) of the monkey was found to yield consistent self-stimulation behavior. Stimulation of this positively reinforcing locus during delivery of painful shock to the ankle resulted in an attenuation by approximately one-third of the pain response. Other loci tested in limbic system produced little or no diminution in pain. Although the mechanism of this phenomenon is not clear, it is suggested that human trials may be warranted if further animal studies confirm the present observation.