Objective To investigate the effects of ketamine on Na+ -K+ -ATPase and Ca2+ -ATPase activity Of cerebro cortex and thalamus in rats. Methods Thirty-two SD rats of both sexes weighing 200-300 g were randomly divided into 4 Groups: 1 control group; 2 anesthesia group; 3 recovery group 1 and 4 recovery group II . In control group normal saline 10 ml?kg-1 was administered intraperitoneally (ip) while in the 3 ketamine groups ketamine 100mg?kg-1 was administered ip. The animals were killed by decapitation when righting reflex was lost (group 2) or recovered (group 3) or when the animals were fully awake (group 4). Brain was immediately removed on ice. Bilateral cortex and thalamus were isolated homogenized and centrifuged. Na+ -K+ -ATPase and Ca2+-ATPase activity were assessed by spectrophotometric analysis. Results The Na+-K+-ATPase and Ca2+ -ATPase activity of cerebrocortex decreased by 32.8% and 26.2% and of thalamus decreased by 31.4% and 24.5% respectively in group 2 as compared with those in group 1. The Na+-K+-ATPase and Ca 2+-ATPase activity of the cerebrocortex and thalamus were recovered in group 3 and 4. Conclusions The Na+ -K+ -ATPase and Ca2+ -ATPase may play an important role in the mechanism of ketamine anesthesia.