The aim of this study was to determine the issues patients worry about when making decisions about cancer treatment. A total of 5,044 colorectal and lung cancer patients from the Cancer Care Outcomes Research and Surveillance Consortium reported their level of worry about (1) treatment side effects, (2) treatment costs, (3) time away from family, (4) time away from work, and (5) transportation to treatment sites. Using multivariable logistic regression, we evaluated the association of sociodemographic, clinical, and psychosocial variables with worry. Overall, 75 % of patients worried about side effects of treatments; 40 %, the cost of treatment; 50 %, time away from family; 52 %, time away from work; and 22 %, about transportation. In multivariable analyses, across all worry domains, older patients had lower odds of reporting worry (p values < 0.001). Patients who perceived less than excellent quality of care, self-assessed their health as less than excellent, and those with a higher cancer stage were more likely to report worry. Asian patients were more likely to report worry than Whites about the cost of treatment and transportation, and relative to Whites, Hispanics were more likely to report worry about transportation (p values < 0.05). Black patients were less likely to report worry about time away from work. Patients worry about issues beyond treatment side effects when making treatment decisions. The pattern of worry varies along sociodemographic, clinical, and psychosocial factors, including race and ethnicity. Understanding the source of patient worry and identifying interventions to alleviate worry are important to delivering patient-centered cancer care. © 2013 Springer-Verlag Berlin Heidelberg.