To investigate the characteristics of incidental pituitary microadenomas, we examined 120 pituitary glands from Korean forensic autopsy cases, from which eight tumors were identified (incidence 6.7%). The average age of the affected subjects was 50 yr (range: 33-96 yr) with a female predominance. The maximum diameters of the tumors ranged from 0.4 to 5.4 mm (mean: 2.8 mm). Immunohistochemical analysis of pituitary hormones revealed three growth hormone-secreting adenomas, one prolactin-producing adenoma, one gonadotropin-producing adenoma, one plurihormonal adenoma, and two null cell adenomas. MIB-1 staining for Ki-67 antigen showed no positive expression. The microvessel density (MVD) of the pituitary microadenomas ranged from 2.3 to 11.6% (mean: 5.3%) and was significantly lower than that of nonneoplastic pituitary glands (11.9-20.1%, mean: 14.8%). Our study provides reference data on incidental pituitary microadenomas in the Korean population.