An experimental investigation was conducted with a combined impacting tee junction in order to study its phase-separation capability for air-water two-phase flows. The combined junction consisted of one horizontal and two vertical impacting tee junctions; all equal-sided with internal diameter 13.5-mm. All experiments were conducted at a pressure of 200 kPa (abs) and ambient temperature. Two sets of data were generated; one set defines the limiting conditions of inlet gas and liquid superficial velocities (J(G1) and J(L1)) for full separation of phases, and the second set shows the improvement in the separation effectiveness of the combined junction relative to a single vertical junction in the region where full separation cannot be achieved. Results show that, compared to a system of a single vertical impacting tee junction, the combined junction significantly increases the limiting values of J(L1) and J(G1) at which full separation of phases takes place. In the region where full separation is not possible, the results show that the combined junction is a much more effective separator than the single junction. The present results for a combined impacting tee junction compared favorably against data of combined branching tee junctions with the same number of branches. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.