Adrenocortical carcinoma (ACC) is a rare endocrine neoplasm originated in cortical adrenal cells with an incidence of 1-2 per million/year and a bimodal age distribution. It is often very aggressive, with a heterogeneous course and a dismal prognosis. The clinical presentation is variable, mostly due to hypersecretory symptoms or to mass effect complaints or as an adrenal incidentaloma. Complete surgical removal is the only potentially curative treatment, although recurrence is common. The most important prognostic factors are tumor stage, resection status, proliferation markers (Ki67, mitotic index) and hypercortisolism. In the present study, we report the first multicenter, retrospective study performed in Argentina with the aim of evaluating ACC clinical presentation, diagnostic methods, therapeutic approach, evolution and predictive parameters in our population. Furthermore, we aimed to find out the correlation between these items and the overall survival (OS) and recurrence-free survival (RFS) periods. Data of 40 patients (F-30 M-10) followed up between 1996 and 2016 was recorded. Median age was 43 years (22-69). Tumor size was 31-200 mm, with 64% being larger than 100 mm. 28% of them were incidentalomas and abdominal pain was the most common symptom. Tumors were hyperfunctioning in 63% of the cases. Cushing syndrome (CS) was the most frequent: 40% with cortisol hypersecretion only and 56% with androgen and/or estrogen co-secretion. One patient presented a primary hyperaldosteronism. An increase of DHEAS, Androstenodione (Δ4A) and testosterone levels was observed in 71%, 100% and 83% of women with hyperandrogenism, respectively; this increase was also observed in 30%, 57% and 50% of women without hyperandrogenism, respectively. In men, 50% had high levels of DHEAS and Δ4A. Adrenalectomy was performed in 39/40 patients, and 18% were operated by laparoscopy. Complete surgical resection was performed in 72% of patients with ENSAT I, II and III. As for staging, 72.5% of patients were in ENSAT stages I and II, while the remaining 12.5% and 15% were in stages III and IV, respectively. Recurrence occurred in 50% of patients with complete surgical removal and 25% presented a locoregional relapse (despite adjuvant treatment with mitotane, EDP, thalidomide or radiotherapy in half of them); 88% of relapsed patients were re-operated and/or treated with the above-mentioned therapies. Mean OS was 103.2 months (95% IC 32-240) and RFS 12 months (95% IC 10-15). Patients without recurrence showed a significantly longer OS than those who recurred (6-288 vs 2-84 months; p=0.023). OS in patients with hypercortisolism was significantly shorter (p=0.0001) tan in those with non-functional ACC. ENSAT I and II patients had a significantly longer OS (2-288 months) than those in stage III (6-66 months) and IV (3-20 months), p=0.003. As for Ki 67, it was determined in less than 50% of the patients. In summary, and in accordance with international reports, the majority of patients presented functional tumors, predominantly CS alone or with androgen/estrogen co-secretion. Androgens were elevated in women either with or without hyperandrogenism. OS was significantly shorter in patients with hypercortisolism. We would like to point out that in our study population, the average OS was relatively long possibly due to the high proportion of ENSAT I- II patients. In conclusion, ACC is a very complex, aggressive and rare malignant disease, with a variable and sometimes unpredictable course. Therefore, these cases must be discussed in a multidisciplinary expert team, consisting of endocrinologists, oncologists, radiologists, surgeons and pathologists in order to offer the best diagnostic, prognostic and therapeutic management in an individualized approach to the ACC patient.