During a period of six years (1985-1990), rotavirus G serotypes were investigated in 104 fecal samples isolates according to an immune enzyme assay using specific monoclonal antibodies against serotypes 1, 2, 3, and 4 of the VP7. The serotypes were established in 65 samples (62.5%) and could not be determined in 39 samples. In the 65 classified serotypes, 7 (6.7%) were found to belong to serotype 1, 23 (22.1%) to serotype 2, 12 (11.5%) to serotype 3, and 23 (22.1%) to serotype 4. The occurrence of the four serotypes during the six years was: serotype 3 was present in three of the six years; serotype 2 was detected in two epidemic outbreaks (1989 and 1990); serotype 3 appeared in the second year and was seen in the remainder of the study; and serotype 4 was present in the six years. We conclude that the four serotypes occur in our population and that future efforts to test the efficacy of any vaccine against this virus should evaluate a protective response against the four serotypes.