Purpose The aim of this study was to evaluate the prevalence of autonomous cortisol secretion (ACS) in patients with primary aldosteronism (PA) and its implications on cardiometabolic and surgical outcomes. Methods This is a retrospective multicenter study of PA patients who underwent 1 mg dexamethasone-suppression test (DST) during diagnostic workup in 21 Spanish tertiary hospitals. ACS was defined as a cortisol post-DST >1.8 µg/dL (confirmed ACS if >5 µg/dL and possible ACS if 1.8–5 µg/dL) in the absence of specific clinical features of hypercortisolism. The cardiometabolic profile was compared with a control group with ACS without PA (ACS group) matched for age and DST levels. Results The prevalence of ACS in the global cohort of patients with PA (n = 176) was 29% (ACS–PA; n = 51). Ten patients had confirmed ACS and 41 possible ACS. The cardiometabolic profile of ACS–PA and PA-only patients was similar, except for older age and larger tumor size of the adrenal lesion in the ACS–PA group. When comparing the ACS–PA group (n = 51) and the ACS group (n = 78), the prevalence of hypertension (OR 7.7 (2.64–22.32)) and cardiovascular events (OR 5.0 (2.29–11.07)) was higher in ACS–PA patients than in ACS patients. The coexistence of ACS in patients with PA did not affect the surgical outcomes, the proportion of biochemical cure and clinical cure being similar between ACS–PA and PA-only groups. Conclusion Co-secretion of cortisol and aldosterone affects almost one-third of patients with PA. Its occurrence is more frequent in patients with larger tumors and advanced age. However, the cardiometabolic and surgical outcomes of patients with ACS–PA and PA-only are similar.