Molecularly imprinted polymers function as synthetic antibodies, binding with specificity to a molecule of a particular shape or exhibiting a specific functional group. The polymers may be applied to numerous fields of research including separations, drug delivery and sensors. In this review, we describe the general properties of imprinted polymers, several production techniques and physical and morphological characteristics, especially for thin films. Particular focus is made with respect to functional states of imprinted polymers and their application as the active component of sensing devices.