Comprehensive mechanistic models for two-phase flow in pipes have been proposed by several authors. These models predict pressure gradients for bubble, dispersed bubble, churn, slug, and annular flow patterns. The churn flow pressure gradient is often formulated based on a homogeneous model or modification of a slug flow model. A new mechanistic model for churn flow in vertical two-phase flow in pipes has been formulated applying two-fluid model concepts. The two-fluid model for churn flow is developed by defining the mass and momentum balances for gas and liquid phases. An interfacial interaction term is introduced to the balance equations defining the interaction between phases. Pressure drops calculated from this model and other methods available in the literature are compared with measured churn flow data from the Tulsa University Fluid flow Projects (TUFFP) databank. Results show that the proposed churn flow model performs better than all other methods considered.