This study explored the use of complementary and alternative medicine (CAM) approaches and their relationship with demographic and disease characteristics and quality of life (QOL) in the primary brain tumor (PBT) population. One hundred one PBT patients were enrolled in this study. The results showed that 34% of patients reported using CAM. Forty-one percent reported using more than one type of CAM. The average cost of each CAM used per month was 69 dollars, with 20% of patients spending more than 100 dollars per month. The majority (74%) reported that their physicians were unaware of their use of CAM. Data analysis found a higher performance status to be the only factor significantly related to use of CAM therapy (P < 0.005). There was no difference in patient report of QOL between users and nonusers of CAM therapies. The high number of patients who do not report CAM use has potential implications for evaluation of symptoms and response to therapy in this population. This may be especially relevant in those patients with higher functional status participating in clinical trials.