Cheese-making is a process that produces multiple coproducts, of which whey is the most abundant in terms of volume. It is often considered a waste product, but whey is rich in lactose, proteins and fats. The aim of the study was to evaluate the environmental impact of the production of whey protein concentrate (WPC) with an ultrafiltration process throughout a life cycle approach. The environmental impacts of three WPCs, characterized by different protein concentrations (WPC35, WPC60, WPC80), were estimated. A scenario analysis was performed to understand the mitigation effect of the pre concentration process carried out in a pretreatment plant to obtain whey with a dry matter content of 20%. Two sensitivity analyses were performed: the first changing the transport distance of whey, the second using a different allocation method. Transportation of the whey was one of the main hotspots in the life cycle assessment performed (28-70%); electricity use accounted for 18-20% of the impact. The alternative scenario, that involves the pre-concentration of whey, obtained a reduction of the impacts from 0.9% to 143%. The pre concentration of whey in a pretreatment plant closer to the cheese factory reduces the environmental burden of the whole process. This occurs even if the energy consumption for pre-concentration increases due to the use of smaller and less efficient devices. (C) 2017 Elsevier Ltd. All rights reserved.