[ABSTRACT] Objectives: study the stages of change in a sample of subjects who presents dependence of different substances, as well as the existence of statistically significant differences between each one of the dependencies and the stage of change that present at the beginning of treatment. Study the processes of change in those heroin addicts subjects of the sample. Material and method: the sample is composed by 163 subjects (23 women and 140 men): 42 display dependence of opiate, 75 of a