The　association　properties　of　poly　(ethylene　oxide)-block-poly　(propylene　oxide)-block-poly(ethylene　oxide)　(PEO　-　PPO　-　PEO)　triblock　copolymers,　commercially　available　as　Pluronics,　in　aqueous　solutions　and　the　solubilization　of　hydrocarbons　in　the　micellar　solutions　are　reviewed.　At　low　temperature　and/or　low　concentration,　the　Pluronic　copolymers　exist　in　solution　as　individual　coils　(unimers).Thermodynamically　stable　micellae　are　formed　with　increasing　copolymer　concentration　and/or　solution　temperature.　In　general,　the　micelle　has　approximately　spherical　shape;　with　hydrophobic　core　and　a　hydrophilic　＇corona＇　around　the　micelle　interior.　Such　a　structure　of　the　micellae　provides　local　hydrophobic　microenvironments　for　organic　compounds　in　aqueous　solution.　Therefore　the　solubilities　of　organic　compounds　in　water　are　strongly　enhanced　in　the　presence　of　the　micellae.　In　virtue　of　their　micellization　as　well　as　the　properties　of　micellar　solubilization,　Pluronic　copolymers　have　essential　functions　in　many　fields　such　as　drug-microcarriers,　micellar　synthesis,　micellar-enhanced　ultrafiltration,　etc.