This article has a purpose, to tell how to measure viscosity, it principles and methods. The article contains information on all types of devices used to measure kinematic viscosity (viscosity measured by gravity). Namely: various gravimetric capillaries (Ostwald, Ubbelohde, Kannon-Fenske, Houillon) and flow cups (ISO 2431, DIN 53211, Ford, Zahn, Engler, Shell). Article also tells about devices that measure dynamic viscosity. Firstly we are talking about capillary viscometers. Describes the structure and work principles of the pressurized capillary viscometers: capillary viscometers utilizing a weight, high-pressure capillary viscometers with electric drive and capillary viscometers utilizing gas pressure. Details are given on the falling-ball and rolling-ball viscosimeters. A large part of the article is given to rotational viscometers (Couette and Searle). Basic principles of work, physical foundations, structure. Article tells about rotational viscometers with a spring (spring type) and instruments with a servo motor. Not disregarded and such are purely technical points, such as various measuring bobs and spindles. The entire section of the article is devoted to the Stabinger ™ viscometer.