Plasma rotation in the collisional regime is considered from the viewpoint of the driftkinetic equation, using orderings which have become standard in neoclassical transport theory. Kinetic arguments require a unique relation between the ion parallel flowUand the radial gradients of density, temperature, and electrostatic potential; this relation is derived and compared to similar relations for collisionless regimes. The off‐diagonal stress tensor component, which governs the time evolution ofUis also calculated. This component does not resemble a viscous stress, and dominates classical viscosity by roughly the usual Pfirsch‐Schlu¨ter factor.