This study examined the effects of streptozotocin (STZ)-diabetes and dietary long chain polyunsaturated fatty acids (LC-PUFAs) on hippocampal N-methyl-D-aspartate (NMDA) receptor subunit expression and lipid peroxidation. MDA level was significantly increased after 8 weeks of STZ-diabetes. LC-PUFAs administration significantly reduced MDA levels in diabetic rats. NR2A and NR2B protein concentrations were significantly decreased by about 30% in diabetic rats. Dietary LC-PUFAs partially restored NR2A and NR2B in diabetic rats whereas the most significant increase was seen in nondiabetic rats. Consequently, dietary LC-PUFAs can partially restore hippocampal NMDA receptors and decrease lipid peroxidation in diabetes. LC-PUFAs arc thus a possible prophylactic means for preventing the cognitive deficiencies of diabetes.