Variations in antibiotic resistance patterns were studied among 178 Shigella strains isolated from 1997 to 2001 in children less than five years of age with acute diarrhea from Colina, a semi-rural community in Santiago, Chile. The minimal inhibitory concentration of several commonly used antibiotics was determined by the agar dilution method. Shigella strains showed high rates of resistance to ampicillin (82%), cotrimoxazole (65%), tetracycline (53%), and chloramphenicol (49%). Furthermore, 51% of the strains showed resistance patterns to multiple antibiotics. Only 9% of the strains were resistant to amoxicillin-clavulanic acid and no resistance was observed to ciprofloxacin, nalidixic acid, or cefotaxime. Continuous monitoring of resistance patterns in Shigella is essential for establishing and updating guidelines for antibiotic treatment in shigellosis.