As recently as 1968, twice as many men as women had peptic ulcer disease in the United States. To determine the current pattern of ulcer disease frequency in men and women, we examined data from the National Center for Health Statistics. These data show that the male predominance in peptic ulcer disease has changed. The male to female ratio is now 1.0 for self-reported period prevalence, and 1.3 for hospitalization and mortality. Ulcer prevalence rates for women have increased whereas rates for men have decreased. For hospitalizations and mortality, the changing sex ratios are primarily due to a more rapid decrease in duodenal ulcer rates for men than for women. Gastric ulcer hospitalizations for women have shown a marked increase for those greater than 65 yr old.