The treatment of Crohn's disease and ulcerative colitis frequently includes potent immunomodulator and biologic therapy to reduce intestinal inflammation, heal fistulae, limit complications, and improve quality of life. These medications may increase susceptibility to and severity of infections, many of which are preventable by preemptive immunizations. Conversely, live-virus vaccines are generally contraindicated in patients receiving immunosuppressive regimens due to risks of vaccine-associated infection. While most patients on immunosuppressive therapies develop immune responses after vaccinations, these may be impaired relative to their nonimmunosuppressed counterparts. This review discusses the rationale for currently recommended vaccinations, as well as issues pertaining to vaccine safety and immunogenicity in immunosuppressed patients with inflammatory bowel disease and their household contacts.