There are effective medications available for the treatment of rheumatoid arthritis (RA); yet, medication adherence remains a problem. In this study, grounded theory methodology was used to investigate the decision-making process used by 30 women with RA when deciding to participate in an evidence-based treatment regimen for this disease. From the study findings, a four-phase process was identified. Pain, life functioning, and exhaustion of health care resources are the components of the initial phase, decision initiation. During knowledge acquisition, the second phase, patients attain information about RA and medications used for its treatment from varying sources. The third phase, trusting the health care provider, is defined by a trusting relationship between patients and health care providers. Patients decide to take or not take medications for RA during the final phase, decision is made. The participating women with RA used a complex decision-making process when deciding to take medications for this disease.