Among other pharmacological properties analgesia is one of the important features of cannabinoids with therapeutical prospects. Cannabinoids have been shown to produce antinociception in experimental animals and humans. Recently a new system of neuromodulation based upon the existence of cannabinoid receptors and their endogenous agonists has emerged. This has been proposed as another of the endogenous pain control systems. Current evidence indicate an interaction between cannabinoid and opioid systems, the latter being of known relevance in nociception. The fact that either exogenous or endogenous opioids enhanced cannabinoid-induced antinociception suggests simultaneous activation of both opioid and cannabinoid receptors by drugs as a new analgesic strategy.