The smoking behavior of an oncology nurse with a long-standing history of smoking was reduced with minimal intervention in a context incorporating the smoker's nonsmoking partner. A prototype support program to parallel the smoker's treatment regimen was developed in which the supportive nonsmoking partner monitored subjective feelings, helped develop a hierarchy of smoking locations, created a viable quitting situation, gave verbal encouragement to the smoker, and assisted in relapse prevention. The smoker's self-reports indicated that the partner played a central role in the quitting process and that sharing the responsibility for quitting (via cooperative roles) was critical to maintaining treatment gains. Partner influence, however, may have also contributed to the smoker's not attaining total abstinence from cigarettes. Limitations of partner involvement in relation to issues of control, as well as the smoker's need for individual responsibility for health behavior change, are discussed.