A methodology is presented to establish the flow profile induced in a spinneret during the spinning of hollow fiber membranes. The flow equations are derived for a power law fluid passing through a concentric annulus. The pressure drop, the velocity profile, the shear stress profile, and the shear rate profile induced during spinning can then be determined. This type of rheological knowledge is useful if membrane structure and properties are to be related to the flow conditions experienced in the spinneret.