INTRODUCTION: Long COVID is defined by National Institute for Health and Care Excellence (NICE) as the set of signs and symptoms that develop during or after a SARS-CoV-2 infection and continue for more than twelve weeks without any alternative diagnosis. One of the most frequent persistent symptoms reported by patients and verified in neuroimaging studies is cognitive dysfunction, due to a generalized hypoconnectivity and a diffuse axonal lesion in white matter. Therefore, the objectives of the present review are to determine how long cognitive functions remain affected during Long COVID and to explore which cognitive functions are most affected beyond three months of follow-up in patients up to 65 years of age without previous neuropsychological or psychiatric complications. METHODS: A systematic review was performed using PRISMA criteria and 11 articles were included through a comprehensive search of five different databases: PubMed, Medline, Scopus, WOS and ProQuest. The risk of bias of the articles was assessed using the Newcastle-Ottawa scale. RESULTS: Cognitive problems in Long COVID persist over time and improve slowly, although studies seem to agree that most areas improved significantly after one year. The cognitive functions that remained impaired the longest were processing speed and attention. CONCLUSIONS: These cognitive alterations cause a reduction in the quality of life of the patients and a reduction in work capacity and manifest the need for a cognitive intervention.