Background Non-tuberculous mycobacteria (NTM) and invasive fungal infections (IFI) may be considered opportunistic infections in immunocompromised patients with GATA2 haplodeciency. Sporadic or familial GATA2 mutations are associated with infection susceptibility, autoimmunity, and myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). This work aimed to investigate GATA2 status in patients with NTM and/or IFI with unknown causes for immunodeciency . Methods A series of incident patients with NTM and/or IFI from the Division of Hematology of the Institute of Infectious DiseasesFIOCRUZ at Rio de Janeiro, Brazil, from 2015 to 2018 were subject to GATA2 genotyping. Patients with HIV positivity or other immunodeciencies were excluded. Results. Twenty-two patients and 9 of their relatives were enrolled. Seventeen patients had IFI, 4 NTM, and one patient present both infections. In 6 patients, the occurrence of malignant disease was found along with this infection, with MDS/AML (n =3) being the most frequent. The pathogenic T354M mutation was found in 4.5% (1/22) of patients and asymptomatic offspring (2/9). We also found the GATA2 polymorphisms rs2335052 and rs369850507 in 18.2% and 4.5%, respectively, and the rs11708606 intronic polymorphisms in 27.3% of cases. Conclusions GATA2 mutations are substantial ndings in patients with NTM and/or IFI without known immunosuppression. As it can indicate a primary immunodeciency and lead to cancers - particularly MDS and AML- the presentation with NTM or IFI should trigger GATA2 mutation testing. The carriers should receive genetic counseling, subsequent infection prevention measures , and surveillance for hematologic malignancies.