An apparatus for properly positioning envelopes in an envelope inserting machine for receiving insert material is disclosed in which the envelope positioning apparatus feeds a first envelope along a prescribed feed path to a predetermined location which is beyond the normal location at which the throat of the envelope can be opened so that the envelope can receive a package of insert material, and then feeds the envelope in a reverse direction until a throat opening device is effective to open the throat of the first envelope. A microprocessor, which controls the feeding of the envelope, is preset to feed the envelope to the first mentioned predetermined location, and has the capability to adjust the preset amount by which the envelope is fed by the amount that it is fed in the reverse direction so that all succeeding envelopes having the same shape and throat characteristics as the first envelope are fed direction to the location at which the throat of the first envelope is opened to receive the insert material.