The gas-liquid mass transfer of a monolith operating in the Taylor flow regime is presented. Mass transfer measurements are compared with a literature model derived for single capillaries. The comparison resulted in a prediction of the unit cell length (gas bubble + liquid slug). Independent measurements of the liquid slug length showed that the predicted unit cell length is close to the measured ones. This leads to the conclusion that mass transfer models for single capillaries may indeed be used for monoliths. Additionally, it is shown that the liquid slug length may also be estimated from pressure drop measurements.