Mitsubishi Heavy Industries, Ltd. (MHI) has developed new high performance turbine blades (reaction blades, impulse blades, and LP end blades) and high performance seals, as new technologies that remarkably improve the performance of steam turbines. Moreover, MHI has developed a new high efficiency steam turbine, adopting not only these new technologies but also other latest technologies to improve performance and operability. The first unit of new high efficiency steam turbine has started the operation at the "T-point" combined cycle verification power plant in Takasago Machinery Works of MHI, and performance and reliability were verified by special measurements. This article describes the characteristics of the new technologies and the structures that were applied to the newly developed steam turbine and the results of the verification.