Abstract Background CD is a multifactorial, heterogeneous, disabling condition, with high surgical rates and complications. Best knowledge of regional clinical features may favor awareness, evolution and healthcare resources. AIM: to describe by means a retrospective study in a Latin American IBD reference center, clinical characteristics of our CD casuistic, and the risk for surgery. Methods data of CD patients (pts) assisted from 1990-June 2020 (CD duration≥1 yr), registered in a database, were revised and reclassified (by Montreal) in Age at diagnosis (A)A1:≦16yrs, A2:17–40, A3:>40, Behavior (B) B1, stricturing (B2), penetrating (B3), perianal modifier (p), Location (L) L1: ileal, L2: colonic, L3: ileocolonic, L4: upper GI: isolated or combined. Incidence rates of progression and surgery (major abdominal surgery and/or bowel resection) were estimated (Kaplan Meier). Results 598 CD pts (M 313, F 285), CD median duration 13.9 yrs (IQR 7.1–21.2) were available for analysis. Montreal A1: n 93 (15.6%), A2: n 335 (56.0%), A3: n 170 (28.4%). Behavior patterns rates within 90 days from diagnosis were: B1: n 523 (87.5%), B2: n 52 (8.7%), B3: n 23 (3.8%). Location L1: n 52 (8.7%), L2: n 368 (61.5%) L3: n 176 (29.4), L4: n 2 (0.33%) and L4 combined with L1, L2, L3: n 47 (7.9%). Complicated initial behavior (or progression to complications) was observed in 252/598 (42.1%). Rates of cumulative incidence of developing either stricturing or penetrating complications at 1, 3, 5, 10 yrs were: 20.9% (95%CI 17.9–24.4), 31.4% (95%CI 27.7–35.4), 37.0% (95%CI 33.0–41.3), 48.4% (95%CI 43.5–53.4) respectively; by each complication were for B2: 15.22%, 22.9%, 27.0%, 34.1%, and B3: 6.7%, 11.1%, 14.6%, 21.9%, respectively. Both complications in same patient were present in 54 (9%) pts. B3 was more prevalent in L3 (40.8%), B2 in L1 (56.3%), (p=0.00001 for both) vs L2 (16.7%, 22.2% respectively). Perianal disease (p) was more frequent in L2 (53.2% p<0.024) vs. the rest of locations (L1: 39.6%, L3: 40.8%, half of L4). CD location progression was less frequent (5%, mainly progression on small bowel). Considerable proportions of pts needed early IV steroids, immunosuppressants (58%), Biologics (at least one: 44%) and optimization. Major surgery was performed in 304/598 pts (50.8%),≥1 in 20%; 9.8% needed permanent stoma. Cumulative incidence rates of major surgery at 90 days, 1, 3, 5, 10 yrs were 5.7%, 11.7%, 23.4%, 29.1%, 42.0%. Patterns B2, B3, L1, L3, L4, A2, also (unusual) A3 were substantial contributors. Conclusion We found high disease burden in this Latin American referral IBD cohort with a large proportion of patients presenting/developing a complicated disease behaviour, with high need for immunosupressive/biological therapy and high rates of major surgery.