This monograph is intended to furnish the engineer up-to-date, practical information for accurately estimating the friction losses in large concrete, steel, and wood-stave pipes running full steady flow conditions. It summarizes experimental information otained through field measurements and large-scale laboratory experiments which the Bureau of Reclamation has compled from worldwide sources over a period of years. Charts are presented for obtaining friction factors for concrete pipe, continuous-interior, full-riveted and spiral-riveted steel pipe, and wood-stave pipe. These will assis the designer in predicting the behavior of a particular conduit.