Ribozymes are RNA molecules that contain a catalytic center. They include RNA enzymes as well as self-splicing and self-cleaving RNAs. A literature survey of ribozyme, covering the period between 1982 and 1992, was performed. Thermodynamic and kinetic aspects are discussed, with emphasis on the kinetics folding pathway of ribozyme L - 19 IVS RNA of Tetrahymena termophila.