The objective of this review is to outline the range of research activities being undertaken on supercritical fluid (SCF) science and technology primarily under the Japanese government funded priority research area on supercritical fluids. The research area is organized into four divisions: I. Solution Structures; II. Equilibrium and Transport Properties; III. Separations and Processing; and IV. Reactions. In division I, simulations and spectroscopic experiments are performed to study the interactions in supercritical fluids and clustering dynamics. In division II, properties of refrigerants, triglycerides and fatty acids, alcohols, and coal chemicals are measured and correlated. In division III, applications of SCF for separating and processing natural products, biomass, coal and coal liquids, polymers, and ceramics are explored. In division IV, homogeneous and heterogeneous reactions are being researched which include carboxylations, photo-induced, Fischer-Tropsch, enzyme reactions, and material conversions. New processes for converting waste cellulose and polymers into chemical intermediates and processes for producing thin films and metal oxides are shown to have great promise. Key objectives of the program and research results are extracted and reviewed from publications and government reports covering the past few years of research activity. In this respect, this review concentrates almost exclusively on Japanese research in supercritical fluids and makes no attempt to review numerous supercritical fluid research in other countries.