A simplified co-rotating twin screw food extruder was designed, fabricated and tested in England, followed by extensive testing in Sri Lanka. It was built as a model to meet the specific product and financial constraints of less developed countries and was expected to be used in those countries to widen the production capabilities of extruded foods. The machine had an estimated delivery of 10 kg/h and was made mainly with mild steel. Two types of screw were made, one with a constant pitch of 14 mm and the other with varying pitch in segments of 14, 12 and 10 mm. The machine was powered by a 2.2 kW electric motor with electronic speed controls. The machine also had electrical heating with a temperature controller and a pressure sensing device. The cost of fabrication of the machine was estimated at pound 2000 with most of the parts built in a fairly simple workshop. A mixture of rice and dried banana was successfully extruded as a potential snack food and on the basis of maximum expansion the best results was obtained from a barrel temperature of 120 degrees C, screw speed 125 rpm, feed moisture 15% and with a die orifice size of 3 mm. When the alternative compression screw was tested very similar results were achieved with no significant improvement in product expansion.