The flowrate measurement of the gas–liquid two-phase flow frequently observed in industrial equipment, such as in heat exchangers and reactors, is critical to enable the precise monitoring and operation of the equipment. Furthermore, certain applications, such as oil and natural gas processing plants, require the accurate measurements of the flowrates of each phase simultaneously. This study presents a method that can simultaneously measure the volumetric flowrates of each phase of gas and liquid two-phase mixtures,QgandQl, respectively, without separating the phases. The method employs a turbine flowmeter and two pressure sensors connected to the pipes upstream and downstream of the turbine flowmeter. By measuring the rotational speed of the rotor and the pressure loss across the flowmeter, the flowrate of the two-phase mixturesQtp= (Qg+Ql) and the gas volumetric flowrate ratioβ= (Qg/Qtp) are determined. The values ofQgandQlare calculated asβQtpand (1 −β)Qtp. This study also investigates the measurement accuracies for air–water two-phase flows at 0.67 × 10−3≤Qtp≤ 1.67 × 10−3m3/s andβ≤ 0.1, concluding that the full-scale accuracies ofQtp,β,Qg, andQlare 3.1%, 4.8%, 3.9%, and 3%, respectively. These accuracies either match or improve the accuracies of similar methods reported in the literature, indicating that the proposed method is a viable solution for the determination of phase-specific flowrates in gas–liquid two-phase mixtures.