Two-phase liquid flows at +5degrees inclination from the horizontal were studied experimentally for mixture velocities between 0.7 and 2.5 m/s and input oil fractions between 10% and 90%. The results were compared with a two-fluid model that includes entrainment. The investigations were performed in a 38-mm ID stainless steel test section, with water and oil as test fluids. Dual continuous flow (both phases remain continuous with inter-dispersion) prevailed, while the two-phase pressure gradient was found lower than the single-phase oil or water. At low mixture velocities the velocity ratio increased with oil fraction while at high ones it decreased. Compared to horizontal flow, water holdup was higher and frictional pressure gradient lower.