There is a growing interest in incorporating informal care in cost-of-illness studies as a relevant part of the economic impact of some diseases. The aim of this paper was to review the recent literature valuating the costs of informal care in a group of selected diseases from 2005 to 2015. We carried out a systematic review on the economic impact of informal care, focusing on six selected diseases: arthritis or osteoarthritis, cancer, dementia, mental diseases, multiple sclerosis and stroke. We selected 91 cost-of-illness articles.