An expanding body of research using the transtheoretical model with both self-change and treatment programs suggests that differences in readiness for smoking cessation are important predictors of successful abstinence. Understanding the cognitive processes underlying these differences may hold tremendous potential for improving the efficacy and efficiency of intervention strategies. Decisional balance theory and self-efficacy theory have been used to help explore how and why people move through the stages of change, but they have been validated almost exclusively with middle-class, educated White samples. This study sought to investigate whether these theories relate to each other in the same manner among low socioeconomic status (SES) primary care outpatients. Results indicated that variables from decisional balance theory (pros, cons) and self-efficacy theory successfully differentiated stage membership and yielded results consistent with the extant literature. Self-efficacy demonstrated the most powerful association with stage membership, whereas pros, cons, and temptations exhibited varying degrees of association. Clinical implications and special considerations when conducting research and implementing interventions with low-SES smokers are discussed.