Lynch syndrome (LS) is the most common inherited colorectal and endometrial cancer syndrome, caused by germline mutations in DNA mismatch repair (MMR) genes. It is also characterized by an increased risk of other tumours with lower prevalence, such as adrenal cortical carcinoma (ACC), an endocrine tumour with an incidence of < two cases/million individuals/year. Most ACC developed during childhood are associated with hereditary syndromes. In adults this association is not as well established as in children. Previous studies showed a 3.2% prevalence of LS among patients with ACC.The objective of this study is to determine the prevalence of ACC in a Spanish LS cohort and their molecular and histological characteristics. This retrospective study includes 634 patients from 220 LS families registered between 1999 and 2018.During the follow-up three patients were diagnosed with ACC (0.47%), all were carriers of a MSH2 germline mutation. The three ACC patients presented loss of expression of MSH2 and MSH6 proteins. One tumour analysis showed loss of heterozygosity of the MSH2 wildtype allele. Our findings support previous data which considered ACC as a LS spectrum tumour.MMR protein immunohistochemistry screening could be an efficient strategy to detect LS in patients with ACC.