Pituitary deficiencies have been reported after traumatic brain injury (TBI) and may contribute to lasting cognitive disorders in this context. In a population of TBI patients with persistent cognitive and/or behavioral disorders, we sought to determine the prevalence of lasting pituitary deficiency and relationships with TBI severity, cognitive disorders, and impairments in activities of daily living (ADL). Fifty-five patients were included (mean age 36.1 years; 46 men) at least 1 year after TBI. They underwent a comprehensive evaluation of pituitary function (basic tests and stimulation), initial TBI severity, and long-term outcomes (cognitive performance, Glasgow Outcome Scale score, impact on ADL, and quality of life [QoL]). We used chi-squared and Mann-Whitney tests to probe for significant (p≤0.05) relationships between pituitary disorders and other parameters. Thirty-eight (69%) patients had at least one pituitary hormone deficiency. Growth hormone deficiency was more prevalent (severe: 40.0%; partial: 23.6%) than corticotropin (27.3%) or thyrotropin (21.8%) deficiencies. Other deficiencies were rare. Growth hormone deficiency was associated with attention and verbal memory disorders and reduced involvement in ADL. We did not find any relationship between pituitary deficiency and the TBI's initial severity. In a multivariate analysis, the TBI severity was introduced as a first factor, and pituitary deficits as a secondary factor for explaining the late outcome (ADL and QoL). In conclusion, TBI patients with cognitive sequelae must undergo pituitary screening because growth hormone, corticotropin, and thyrotropin deficits are particularly common and can adversely affect ADL and reduce QoL.