ObjectiveTo evaluate the frequency of different types of cancer in patients diagnosed with hypothyroidism using big data methodology on the Savana Manager platform. MethodsAn observational, retrospective study was carried out using electronic medical record (EMR) data from the Hospital Universitario Puerta de Hierro Majadahonda (Madrid). Information from the EMRs was extracted using artificial intelligence techniques and analysed using the Savana Manager v3.0 software. Searches were performed using the term “hypothyroidism” and the terms corresponding to the tumours analysed. ResultsOf a total of 506,749 patients studied, 23,570 (4.7%) were diagnosed with hypothyroidism. Patients with this diagnosis had a significantly higher frequency of cancer than that found in non-hypothyroid subjects (OR 2.09, 95% confidence interval [CI] 2.01-2.17). This higher frequency was found both in women (OR 1.99, 95% CI 1.90-2.08) and in men (OR 2.83, 95% CI 2.63-3.05). However, this higher frequency of cancer was not observed in hypothyroid patients older than 60 years (OR 0.97, 95% CI 0.92-1.02). Although the frequency of most of the neoplasms studied individually was higher in those with hypothyroidism, we observed that hypothyroid patients over 60 years of age had a significant decrease in the frequency of prostate, lung, colorectal and liver cancer. ConclusionData from this hospital cohort suggest that there is a significant association between a diagnosis of hypothyroidism and cancer. However, this association is less evident in hypothyroid patients older than 60 years.