Reports in haematology, transplantation medicine and rheumatology indicate that Rituximab, a B cell depleting therapy, increases the risk for Pneumocystis jiroveci pneumopathy. Patients with ANCA-associated vasculitis have an increased incidence of Pneumocystis jiroveci pneumopathy compared to other autoimmune diseases and Rituximab is often used to induce and maintain remission.Herein we present a case of a patient with granulomatosis with polyangiitis treated with Rituximab for relapse that developed Pneumocystis jiroveci pneumopathy 3 months after and we review the relevant literature to assess Pneumocystis jiroveci pneumopathy incidence and risks factors under Rituximab. We also discuss whether pneumocystis jiroveci screening before Rituximab and Pneumocystis jiroveci pneumopathy prophylaxis under Rituximab are indicated.Pneumocystis jiroveci colonization is found in 25% of patients with autoimmune diseases. However the association between colonization and Pneumocystis jiroveci pneumopathy development is not very strong.Pneumocystis jiroveci pneumopathy incidence in ANCA-associated vasculitis patients treated with Rituximab is found to be 1.2%. Therefore evidence and practice do not support the use of Pneumocystis jiroveci pneumopathy chemoprophylaxis in all ANCA-associated vasculitis patients receiving Rituximab. CD4 cell count cut-off does not work well in patients treated with Rituximab as it does not reflect T-cell impairment following B cell depletion.To help stratify the risk of both colonization and Pneumocystis jiroveci pneumopathy development, assessment of the patient's net stat of immunodeficiency before administering Rituximab -including age, renal or lung involvement, previous infections due to T cell dysfunction, blood tests (lymphocytopenia, low CD4 cell count) and concomitant therapy -is warranted.