This issue of Hypertension Research contains the review and original articles presented at the International Symposium on Natriuretic and Digitalis-Like Factors held in Chitose, Hokkaido, Japan, on August 24, 1999. The symposium was the satellite meeting of the 9th International Conference on the Na/K-ATPase and Related ATPases, which was held in Sapporo, Hokkaido. At the symposium, it became clear that ouabain is the most promising candidate for a circulating hormone to regulate a number of physiological functions, including hypertension, and that other minor substances may also exist as endogenous digitalislike factors. Most of the symposium contributors submitted papers to this journal. I am going to summarize briefly the research history and current research results on endogenous digitalislike factors (EDLF).