Abstract: An annular co-extrusion die for extruding multi-layer tubular plastic film has inner die members stacked one upon another and having radially outwardly extending surfaces forming radially outwardly extending helical passages between respective pairs of inner die members. An annular outer die member surrounds the stacked inner die members and forms a longitudinally extending annular passage therebetween for conveying plastic material from the radially outwardly extending helical passages to an annular extrusion orifice. A lower inner die member has a first feed passage extending from a lower surface thereof to a substantially horizontal upper surface thereof at a position spaced from a central longitudinal axis of the longitudinally extending annular passage, the substantially horizontal upper surface having a first groove extending from the upper end of the first feed passage to the longitudinal axis.