The purpose of this study was to assess trends in diabetes in pregnancy in American Indian and whites mothers in Montana and North Dakota. Montana and North Dakota birth records were utilized to assess trends in any diabetes in pregnancy in American Indians and whites from 1989 to 2000. From 1989 through 2000, there were 133,991 and 102,232 births in Montana and North Dakota, respectively. The majority of mothers were American Indian (11%) or white (87%). The rate of any diabetes in pregnancy increased significantly in Montana Indian (3.1-4.1%, p = 0.04) and white mothers (1.8-2.6%, p < 0.001) from 1989-1991 to 1998-2000. The rate also increased significantly in white North Dakota mothers (1.6-3.2%, p < 0.001), but the increase in rate for Indian mothers in North Dakota did not reach statistical significance (3.8-4.8%, p = 0.06) during this time period. In each time period, Montana and North Dakota Indian mothers were more likely than white mothers to have any diabetes in pregnancy. The rate of diabetes in pregnancy has increased in American Indian and white mothers. Thus public health programs are now facing an increasing number of women with a history of GDM at future risk of type 2 diabetes and an increasing number of offspring of diabetic pregnancies at risk for becoming overweight and developing type 2 diabetes at a young age.