The velocity of Taylor bubbles in inclined pipes is reduced if a lubricating liquid film between the bubble and the pipe wall is not present. An analytical model predicting the gravity-driven drainage of the lubricating film is presented in this article. The model is then used to establish a criterion for film breakup: ift bubble = t bubble /τ < 0.01 the thin film would not break up, where t bubble is the bubble's passage time, and τ is the characteristic film drainage time based on the fluid properties, pipe geometry, and critical film thickness. The model is validated experimentally with Taylor bubbles in inclined pipes (5• to 90• , the latter being vertical) of stagnant liquids (ethanol, methanol, and mixtures of deionized water and methanol).