The loss coefficients for smooth, sharp-edged tees of circular cross-section with the area ratio of 11.44 were determined experimentally for five branch angles which ranged from 45 deg to 135 deg giving special consideration to all configurations of flow through the tees. The Reynolds number, in the leg carrying the combined flow, was kept to a constant value, i.e., 10 5 for the branch pipe and 3ϫ10 4 for the main pipe, respectively. The equations for loss coefficients developed from the continuity, energy, and momentum principles give good agreement with the experimental results for tees with large area ratios provided that correction factors are introduced. The correction factors were determined by the analysis of the experimental data with the relative uncertainties from 0.9 to 3.3% according to the configurations of flow. The results constitute a useful guide to the determination of the loss coefficients for tees with large area ratios.