Recipients of hematopoietic cell transplantation (HCT) are at risk for potentially preventable infectious complications because of defects in humoral and cell-mediated immunity. Studies of vaccine immunogenicity in HCT recipients have shown that antibody response rates depend on age, type of vaccine, and presence or absence of graft-versus-host disease. However, few large-scale studies have assessed the immune response to vaccination in HCT recipients. Additionally, HCT recipients have much higher rates of potentially preventable infections compared with the general population even after vaccination. This review evaluates the available studies and our view on the measurement of specific antibody titers, definition of an immune response, and durability of response in HCT recipients in both inactivated and live attenuated vaccines.