The role of health knowledge in consumer use of nutritional labels on food packages is explored using data from the 1995 Diet and Health Knowledge Survey. Two types of label use models, a binary choice label use model and a level of label use model, are employed with particular attention given to the endogeneity of health knowledge. The binary choice model is concerned with factors affecting the probability of label use. The level of label use model deals with factors affecting the number of food products in which label use occurred. The results show that health knowledge has a significant role in increasing label use.