Although less common than aqueous-based foam, non- aqueous foam has numerous uses in a broad range of industries. The vast quantity of work on understanding foam has been conducted on aqueous systems and many of the underlying concepts concerning foam generation and stability can be applied to non-aqueous systems. In both type of systems, high surface viscoelasticity, and barriers that prevent foam-film rupture promote foam stability. However, the low gas/liquid surface tension of non-aqueous systems limits adsorption to their gas/ liquid interface and reduces the possibility of generating stable foam films. Certain specialty surfactants have been found to provide stable oil-based foam, and parti- cles having adequate wetting properties can adsorb to the interface and block foam-film rupture. Furthermore, binary liquid systems and multi-phase condensed media have proven to be effective in stabilizing non-aqueous- based foam. Extended these principles to different types of non-aqueous fluids will surely lead to new foaming systems and applications. Some of the most important and complex non- aqueous foams are found in the petroleum industry. Bituminous, asphaltenic and heavy oils can readily foam upon depressurisation during gas separation processes. These foams can persist for several hours or days delay- ing the processing of the oil and causing damage to the equipment (corrosion, cavitation, reduction of effi- ciency, etc.). For this reason it is essential to use additives that prevent the formation of foam (antifoams) or destroy foams already created (defoamers). To date most of the available additives have been optimized for aqueous-based systems and while they can be effective on certain crude-oil foams, particular aspects of the crude oil must be taken into consideration to develop new and more robust foam control formulations.