Trichoderma species are filamentous fungi that were previously considered to be culture contaminants. We report 2 well-documented cases of invasive Trichoderma infections, and we comprehensively review the literature on this topic. Trichoderma species are mainly responsible for continuous ambulatory peritoneal dialysis-associated peritonitis (7 cases) and invasive infections in immunocompromised patients (9 cases) with a hematologic malignancy or solid-organ transplant. Definitive diagnosis is difficult to achieve because of the lack of specific diagnosis tools. Species identification can benefit from a molecular approach. Trichoderma longibrachiatum is the most common species involved in these infections. Regardless of the type of infection, the prognosis was poor, with 8 deaths among 18 cases. This may be partially because of the resistance of these organisms to the majority of available antifungal agents, including amphotericin B. Trichoderma species now should be added to the growing list of emerging filamentous fungal pathogens.