Toxoplasmosis can be a severe opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS), and also among solid organ transplant and allogeneic hematopoietic stem cell transplant (HSCT) patients. Patients with low-grade or chronic hematologic malignancies are treated with increasing immunosuppressive regimens and, therefore, represent an emerging population at risk for opportunistic diseases. We report here two cases of disseminated toxoplasmosis occurring in non-allografted hematologic patients with chronic lymphoproliferations. A review of 44 cases from the literature reveals that toxoplasmosis occurs increasingly in indolent B cell lymphoproliferative disorders. Aggressive lymphoproliferations, adenosine analogs, autologous HSCT, and the absence of chemoprophylaxis are the main risk factors for opportunistic toxoplasmosis. The central nervous system is the main organ involved. Fever is only present in half of all cases. Latent Toxoplasma cysts reactivation (LTCR) is the most common, but primary infection occurs in about 20% of cases. Global mortality is over 50%.