There are numerous applications where a voice coil actuator is used for position control and it is not desirable to have a physical position sensor for feedback. This paper proposes a technique for sensorless position estimation of a linear voice coil transducer using sliding mode observers. The method exploits the fact that some voice coil designs possess position-dependent force and back-emf parameters due to their geometrical properties. Using an observer structure that incorporates these position-dependent parameters of the transducer allows the coil position to be observed from a current measurement. The nonlinear model developed for the voice coil is validated and experimental results are presented and discussed. Observability is proven and the results are incorporated into a sliding mode position feedback control algorithm.