Gastrointestinal infections are a frequent and important complication of immunodeficiency diseases and immunosuppressive therapy. Such infections may be severe, prolonged, or even fatal, whereas the same infections are typically mild and transient in immunocompetent persons. In this regard, the strong association between HIV-induced immunosuppression and the increased prevalence of severe enteric infections is strong evidence of the link between immune function and defense against enteric pathogens. Because gastrointestinal infections in immunocompromised persons are frequently severe and life-threatening, a vigorous approach to the diagnostic evaluation and therapeutic management is advocated by many clinical investigators. In this review, we summarize the important new developments, particularly during the past year, regarding gastrointestinal infections in immunocompromised persons.