To gain more insight into interspecies transmission of rotavirus group A, human and animal fecal samples were collected between 1997 and 2001 in The Netherlands. A total of 110 human stool samples were successfully P and G genotyped by reverse transcriptase PCR. All strains belonged to the main human rotavirus genotypes G1 to G4, G9, [P4], [P6], [P8], and [P9]. [P8]G1 was predominant, and 5.5% belonged to the G9 genotype. Eleven percent of all P[8] genotypes could be genotyped only by a recently published modified primer. Rotavirus-positive fecal samples from 28 calf herds were genotyped by DNA sequencing. Genotypes G6 and G10 predominated; G6 and G10 were detected in 22 (78.6%) and 16 (57.1%) of the rotavirus-positive calf herds, respectively. In 12 (42.9%) calf herds, we found mixed infections. Genotype G8 was not found. Genotype G6 bovine rotaviruses were divided into three clusters: UK-like, VMRI-29-like, and Hun4-like. DNA sequencing of a part of the VP7 gene was shown to be useful as a quick determination of uncommon or novel strains of which the genotyping cannot be done by genotyping PCR. Of equine strains, both VP4 and VP7 genes could be used for genotyping: two [P12]G3 and four [P12]G14 equine rotaviruses were determined. We did not find indications for rotavirus interspecies transmissions, although the recently published human G6-Hun4 is genetically related to our G6 bovine isolates. All bovine, porcine, and equine rotaviruses were within genotypes previously reported for these animal species.