Rotavirus strains detected as part of ongoing strain surveillance in Cameroon, and whose first-round reverse transcription-PCR product could not be genotyped by using conventional genotyping primers, were subjected to sequence analysis for strain characterization. We detected for the first time in Africa a human rotavirus with G5 specificity. The Cameroonian G5 strain had a short electrophoretic pattern and was of VP6 subgroup I specificity and a VP4 P type. The VP7 gene shared a higher nucleic acid and amino acid homology with the porcine G5 strain CC117 (90 and 96%, respectively) than with human G5 strain IAL-28 (86 and 92%, respectively). Phylogenetic analysis showed Cameroonian strain MRC3105 clustered together in the same lineage as two other reported porcine G5 strains. The Cameroonian G5 strain, the first to be reported in humans outside of Latin America, may be a natural reassortant between animal and human rotavirus strains.