Gas–liquid two-phase flows in which gas is dispersed in liquid occur in various fields, from natural to industrial processes. Key parameters of two-phase flows were simultaneously measured using synchrotron X-ray imaging. Phase-contrast imaging with digital image processing methods was applied to obtain microbubble data. Void fraction was obtained from X-ray absorption. Developed method was validated with both simulated and experimentally acquired X-ray images. The results confirm that various features of two-phase flows can be simultaneously measured with high spatial and temporal resolutions. This technique would be useful in the design and performance evaluation of two-phase flows in practical applications in which microbubbles move at high speed.