Package downsizing is a practice where the package content is reduced without changing the package or the price of the product. In a market that is defined by ‘hyper-competition,’ package downsizing is often practiced by marketers to effect an invisible price increase for their products. Although marketers may maintain that providing, the legally required, quantity indication on the package is adequate for customers to make logical and informed choices, research indicates that consumers often do not consult quantity indications on packages (...) but use alternative methods (e.g., visual impressions of the package size, total package price, or previous purchase experience) to judge product quantity and to calculate product value. As a subtle means, package downsizing therefore has the potential to mislead customers in the buying process due to an unfavorable balance of information within the dyad. This could give rise to serious moral and ethical consideration. In this paper, we examined various issues related to package downsizing, such as why sellers resort to this type of practice, consumer vulnerability to package downsizing, as well as the extent of protection offered to consumers by the existing laws and regulations with respect to product packaging. Finally, we examined the ethics of package downsizing using the existing legal, moral, and professional ethical standards as well as the principle of equivalence. Our analysis indicates that package downsizing, as it is practiced by the marketers and sellers today, is unethical as far as the consumers are concerned. (shrink)