PURPOSE: To provide a thread feed unit for circular knitting machines, simple in structure and flexible in operation.

CONSTITUTION: This thread feed unit 1 has a supporting block 2 which can be associated with a knitting machine laterally to one or more cylinders 3, and is provided with at least one thread guide 4 which has a body 9 provided with an elongated configuration associated with a supporting element 7 and slidable along a direction substantially parallel to its longitudinal extension. The supporting element 7 is associated with the supporting block 2 for oscillation about an oscillation axis 8a transverse to the sliding direction of the thread guide body 9. A first thread guide actuator 16 is provided and controllably acts on the supporting element 7 to oscillate the thread guide 4 about the oscillation axis 8a, and second actuators 21, 22 controllably acts on the thread guide body 9 to slide it longitudinally with respect to the supporting element 7.