We have recently demonstrated that nicotine administration improves the acquisition and/or memory retention of aged rats in 17-arm radial maze, Lashley III maze, and one-way active avoidance testing. The present study extends our evaluation of nicotine's cognition-enhancing potential by determining the effect of nicotine on acquisition and retention of the Morris water maze in young adult (2 to 3 months old) and aged (25 to 26 months old) Sprague-Dawley rats. For 3 days prior to the onset of testing, and 15 min prior to daily testing, rats were treated IP with 0.2 mg/kg nicotine or saline vehicle. Compared to the performance of young adults, vehicle-treated aged rats were impaired in water maze acquisition. Nicotine substantially enhanced the acquisition of aged rats. Furthermore, nicotine significantly improved the memory retention of young adult rats. These cognitive improvements may involve a nicotine-receptor induced increase in generalized alertness and/or a facilitation of higher integrative function. The results suggest that nicotine and/or nicotinic agonists may be useful in treating age-associated memory impairment and/or Alzheimer's disease.