Abstract The viscosity values of different samples of latex diluted to different degrees were measured by means of three viscometers of different types, viz., the Brookfield viscometer, the Epprecht viscometer, and the French Rubber Institute viscometer. The results obtained are dependent on the type of apparatus, although within certain limits, the Epprecht and French Rubber Institute viscometers give approximately the same results. The values obtained with the Brookfield viscometer are distinctly different from those with other two viscometers. In spite of these differences, however, each of the viscometers has a field of use, which is indicated and discussed.