Rates of diabetes and its complications have reached epidemic proportions among North American Aboriginal peoples. This appears largely due to changes in diet and activity levels associated with a shift away from traditional lifestyles. Since exercise has been shown to be effective in preventing non-insulin-dependent diabetes mellitus (NIDDM), Aboriginal communities may be able to reduce their rates of the disease by incorporating exercise programs into their public health programs. We describe a pilot project in Saskatoon, Saskatchewan, whose ultimate purpose is to evaluate the effect of exercise in preventing gestational diabetes. If successful, this would reduce the risk of developing NIDDM for both women and their offspring.