Knitted wire-mesh mist eliminators have widespread application in many industrial plants. Despite their extensive use, the open literature regarding them is really limited. Some experimental data and mechanistic models have been published for common knitted wire-mesh mist eliminators formed from a single metal pad. This type of mist eliminator can be used in most distillation and absorption columns, but because of the poor removal efficiency, cannot be used in operations involving acid mist, fine fog resulting from liquid condensation from a saturated vapor, oil mist from compressed gases, and natural-gas dehydration applications. Moreover, other possible problems may arise when the separator is fed with high liquid and gas flow rates, because these conditions can induce flooding in the mist eliminator. In both of these cases, common wire-mesh mist eliminators do not perform satisfactorily, and therefore complex wire-mesh mist eliminators have to be installed to improve separation efficiency or to increase allowable liquid loadings while avoiding flooding phenomena. This article presents a mechanistic model based on a set of new experimental data obtained by investigating performance of commercial complex eliminators.