The main purposes of this study were to explore the ways to empiricaly measure the product use efficiency and to examine the relationships between the use efficiency and other variables. Use efficiencies for clothes, electrical appliances and food were actually measured by employing a diary method. Twenty eight home makers in Korea, specifically those residing in Seoul and its vicinities, participated in recording their use of the products for 30 days. The results indicated that actual use efficiency was not related to perceived efficiency and attitudes toward conservation. Some indices within a product group showed positive correlations with each other, but overall the results strongly suggested that use efficiency is a multi-dimensional concept specific to respective products or product groups.