DiGeorge syndrome (DGS) is one of the most frequently seen chromosomal abnormalities. The major genetic cause of DGS is a microdeletion on chromosome 22q11.2. Majority of the cases are diagnosed during their childhood. DGS is rarely considered and diagnosed in adulthood. Herein, we report the first case of a patient with DGS and azoospermia in the literature. Our patient was a 35-year-old male with mild dysmorphic features, hypernasal voice, mental retardation, and azoospermia. His laboratory tests and echocardio-graphic assessments were normal. Clinical clues to DGS were hypernasal voice and dysmorphic features with mild mental retardation. The diagnosis of DGS was confirmed by fluorescence in situ hybridization ( FISH). Negative effects of cognitive disorders on reproductivity are already known; however, we haven't find any studies in the literature that evaluated infertile patients with DGS using semen analysis, apart from these potential unfavourable effectc of cognitive disorders. Coexistence of DGS and azoospermia may be completely coincidental, but azoospermia can be also one of the unknown clinical features of this syndrome. Many patients with a mild phenotype of DGS may be underdiagnosed. DGS should be considered in adults who have mental, behavioral, or psychiatric disorders with mild dysmorphic features, even in the absence of classical features.