A lapping monitor for monitoring the lapping of a lapping surface of a body having at least one transducer which has a height that has to be lapped. The lapping monitor has a lap unit for lapping the lapping surface, at least one lapping indicator mounted close to the transducer to indicate the height of the transducer and a control block in the body at a certain distance from the lapping indicator or indicators. It is also possible to use a property of the transducers themselves, e.g., their resistance, to indicate their height. The control block receives indication of the height of the transducers being lapped from the lapping indicators or from the transducers via an electrical connection. The control block is further equipped with test contacts for establishing an external connection. The lapping monitor is particularly well-suited for performing 4-point resistance tests of the lapping indicators or transducers and can be effectively employed in lapping rows of magnetoresistive transducers such as MR or GMR heads to accurate heights.