Organ and stem cell transplant patients are at risk for foodborne illness due to disease and medically induced immunosuppression. The food safety knowledge and informational needs of these groups have not been documented in the literature. The objectives of this study were to assess transplant patients' food safety knowledge and perceptions, to probe the likelihood of practicing safe food handling behavior, and to test an educational strategy for future food safety interventions aimed at transplant patients. Subjects were organ or stem cell transplant patients, or their family care providers. Research was conducted in inpatient or outpatient facilities at a large, Midwestern United States comprehensive cancer and transplant center. Differences in survey data between the organ and stem cell transplant groups were determined by Student's t tests. Ethnographic methods were used to analyze qualitative focus groups and interview data for themes. Organ transplant patients had less motivation to follow food safety recommendations than did stem cell transplant patients, and they were more likely to consume risky foods. Stem cell transplant patients overall had a better understanding of their susceptibility to foodborne illness and had better prepared themselves with the knowledge and behavior changes needed to protect their health. Educational materials aimed at communicating food safety information for transplant patients were evaluated by patients and judged acceptable. This study found that organ transplant and stem cell transplant patients are distinct patient populations, with differing perceptions regarding the seriousness of foodborne illness and willingness to adopt preventative food handling practices. Population differences should be accounted for in food safety educational strategies.