A cross-sectional design with 190 smokers and exsmokers selected by random digit dialing was used to determine differences in processes individuals use to modify behavior across five stages of smoking cessation. Five stages of cessation are: precontemplation, contemplation, recent quitting, long-term quitting, and relapse. Ten processes of change (POC) or ways individuals modify behavior were assessed. Examples of POCs are: consciousness raising, self-liberation, reinforcement management, and stimulus control. Biochemical validation of smoking abstinence was performed on a random subset of exsmoker subjects. Individuals in five stages of smoking cessation used processes of change differently as reflected by a significant MANOVA, F (40,590) = 5.02, p = .0001. It is important to assess an individual's stage of smoking cessation when planning interventions related to POCs.