IEC 61362:2012 includes relevant technical data necessary to describe hydraulic turbine governing systems and to define their performance. It is aimed at unifying and thus facilitating the selection of relevant parameters in bidding specifications and technical bids. It will also serve as a basis for setting up technical guarantees. The scope of this standard is restricted to the turbine governing level. Additionally some remarks about the control loops of the plant level and about primary and secondary frequency control (see also Annex B) are made for better understanding without making a claim to be complete. Important topics covered are: – speed, power, water level, opening and flow (discharge) control for reaction and impulse-type turbines including double regulated machines; – means of providing actuating energy; – safety devices for emergency shutdown. To facilitate the setting up of specifications, this guide also includes data sheets, which are to be filled out by the customer and the supplier in the various stages of the project and the contract. Acceptance tests, specific test procedures and guarantees are outside the scope of the guide; those topics are covered by IEC 60308. This second edition cancels and replaces the first edition published in 1998. It is a technical revision. It takes into account the experience with the guide during the last decade as well as the progress in the state of the art of the underlying technologies. Keywords: Hydraulic turbine, Hydraulic turbine governing systems.