The prevalence of glucose intolerance and diabetic complications was determined in second-generation Japanese-American (Nisei) women and compared to previously obtained results in Nisei men. A volunteer study sample of 191 Nisei women 45-74 years old was enrolled from a study population of 1489 Nisei women born 1913-1942, raised and educated in the U.S., and residing in King County, Washington. The enrolled sample included 72 with normal glucose tolerance, 67 with impaired glucose tolerance (IGT), and 52 with non-insulin-dependent diabetes. A random sample was also drawn from the study population to form a reference sample of 157 women. Based upon observations in the reference and enrolled samples, an estimated 16% of Nisei women in the study population have diabetes and 40% IGT. These rates compare to 20% diabetes and 36% IGT previously estimated for Nisei men 45-74 years old. The prevalence of cardiovascular disease (hypertension, peripheral vascular disease, and/or coronary heart disease) was highest among diabetic women, lowest in those with normal glucose tolerance, and intermediate in women with IGT. In comparison to diabetic men, there was a significantly lower frequency of neuropathy, peripheral vascular disease, and coronary heart disease in diabetic women. However, hypertension occurred equally often in both. Thus Japanese-American men and women 45-74 yr old have a similar prevalence of glucose intolerance, although less severe in women, and complications, except for hypertension, are reduced in women.