From June 1992 to May 1993, rotaviruses were detected by an immunoenzymatic assay in 159 (49.5%) of 321 children admitted to the hospital with acute diarrhea. Of the 159 cases ELISA positive, 80 samples were chosen at random to investigate subgroups and serotypes of group A human rotavirus. By the ELISA test 9 (11.3%) of the strains were subgroup I, 46 (57.5%) were subgroup II, and 25 (31.3%) could not be grouped. The serotype G1 was identified in 52 cases (65%), G2 in 11 cases (13.8%), G3 in 1 case (1.2%), and 7 cases (8.8%) showed more than one serotype. By electrophoretic analysis of viral RNA, 137 (42.7%) of the samples exhibited an RNA pattern. The long pattern (59.1%) prevailed over the short pattern (35.8%), and by coelectrophoresis 8 different electropherotypes were found throughout the period of study. These results illustrate the great variety of rotavirus strains in this region of the country.