1. The effects of the 5-HT1A receptor agonist, (8-OH-DPAT), alone and in combination with the selective 5-HT1A antagonist, WAY-100635, were assessed in Fischer-344 rats in an 8-arm radial maze. 2. At a dose of 1.0 mg/kg, 8-OH-DPAT significantly reduced both efficiency of performance (% correct arm entries) and response rate (arms/min) compared with the saline condition. 3, These effects were completely blocked by WAY-100635 which by itself had no effect on efficiency or response Fate. 4. WAY-100635 inhibits 8-OH-DPAT-induced impairment in radial maze performance.