The quantum properties of a particle interacting with a dissipative environment are studied. We show the way in which different types of environments reduce quantum effects. The influence of certain environments, like that described by a Caldeira‐Leggett bath of oscillators suppress very efficiently interference processes, while the coupling to other (ohmic) environments does not modify qualitatively the main features of a free particle. Examples of physical realizations of the different environments are also given. © 2003 American Institute of Physics