In spite of increasing expansion of numerical modeling, the model research of hydraulic machines is being used for experimental verification of the hydraulic machine on the model. Tests of physical models are the essential part of research and development of large and medium-sized hydraulic turbines. Even the best math model cannot replace the actual behavior of the machine under similar conditions, which will affect the real plant. The book deals with issue of the model tests on the model Francis turbine. In the first part, theory of model tests and the theory of similarity are mentioned. The second part focuses on model research and measurement in practice. There are examples of measurement results, such as tables, graphs, characteristics; it further describes variables, constants, and formulas necessary for the correct measurement and evaluation of data, basic principles and procedures for the measurement. From the initial stages (production, appropriate choice of sensors) to the final results of measurements with calculation of uncertainties on the performed measurement. The book is supplemented with photos. The book serves students and those who are interested in this issue.