This paper reports the application of novel, digital image analysis techniques in the study of slug flow characteristics, under dynamic conditions in two-phase gas-liquid mixtures. Water and anoil of viscosity 18 cP were used for the liquid phase and carbon dioxide was used for the gas phase. Flow in a 75-mm i.d., lO-m long acrylic pipeline system was studied. Images of slugs were recorded onvideo by S-VHS cameras, using an audio-visual mixer. Each image was then digitized frame-by-frame andanalyzed on a SGIࡊ workstation. Detailed slug characteristics, including liquid film heights, slug translational velocity, mixing length, and, slug length, were obtained. © 1998 by ASME.