Prolonged exposure to ketamine, a NMDA receptor antagonist, results in accelerated neurodegeneration and attenuated weight gain in neonatal rats. Suppression of the NMDA receptors by non-competitive antagonists has resulted in conflicting reports of both increased and decreased expression of BDNF. To examine the effect of prolonged ketamine exposure on BDNF expression, we administered saline or ketamine (20 mg/kg) at 90-minute intervals over 9 hours to postnatal day 7 (P7) rat pups. The ketamine-treated rat pups had increased neurodegeneration, BDNF and TrkB cDNA products and protein levels. This increased expression of BDNF may be a response to ketamine-induced injury.