Clostridium difficile infection (CDI) affects significant numbers of hospitalized patients and is an increasing problem in the community. It is also among the most commonly isolated pathogens in HIV patients with diarrheal illness and is ≥2 fold more common in HIV-seropositive individuals. This association is stronger in those with low absolute CD4 T cell counts or meeting clinical criteria for an AIDS diagnosis, and was most pronounced before the wide availability of highly active antiretroviral therapy. The presentation and outcome of CDI in HIV appears similar to the general population. The increased risk can in part be attributed to increased hospitalization and antimicrobial use, but HIV related alterations in fecal microbiota, gut mucosal integrity, and humoral and cell mediated immunity are also likely to play a role. Here we review the evidence for these observations and the relevance of recent advances in the diagnosis and management of CDI for the HIV clinician.