Cancer rates in the province of Nova Scotia, Canada, are among the highest in the country and coincide with elevated rates of risk factors such as smoking, poor diet, and obesity. To investigate the importance of diet on cancer, using data from the 1990 Nova Scotia Nutrition Survey, we developed a diet quality score reflecting compliance with 17 nutrient recommendations. The survey data were subsequently linked with the provincial cancer registry, and the relationship between diet quality and cancer was quantified using logistic regression. Our results support an inverse relationship between diet quality and cancer, although limited statistical power resulting from our small study sample did not reveal any statistically significant relationships. We estimated that cancer incidence could potentially be reduced by approximately 35% through improved diet quality. On the basis of poor diet, nutrition-related factors (high body mass index), our estimates of the preventable fraction of cancer, and the high provincial cancer rates, we recommend health promotion strategies aimed at improving diet quality in Nova Scotia.