This study examines whether there are differences in men's and women's use of computers and the Internet in the United States and Japan and how any such gender gaps have changed over time. The authors focus on these two countries because information technology is widely used in both, but there are substantial differences in institutions and social organizations. They use microdata from several surveys during the 1997-2001 period to examine differences and trends in computer and Internet usage in the two countries. Their results indicate that there were significant gender differences in computer and Internet usage in both countries during the mid-1990s. By 2001, these gender differences had disappeared or were even reversed in the United States but remained in Japan. People not currently working have lower levels of IT use and skills in both countries regardless of gender, but working women in Japan have lower levels of IT use and skills than working men, a difference that generally does not occur in the United States. This finding suggests that employment status per se does not play a large role in the gender gap in Japan, but type of employment does. The prevalence of nonstandard employment among female workers in Japan accounts for much of the gender gap in IT use and skills in that country. (Contains 11 footnotes and 6 tables.)