Picobirnavirus, a novel group of viruses recently detected in children and several species of animals including chickens, are different from the existing members of the family Birnaviridae. Picobirnavirus (PBV) is the tentatively proposed name for the group of these viruses. These viruses are 30-40 nm in diameter and have icosahedral symmetry with triangulation number (T) equal to 3. Their buoyant density in CsCl is 1.4 g/ml. Their genome is bi- or trisegmented double-stranded RNA (dsRNA) with segment lengths of 2.6 and 1.9 kbp for bisegmented and 2.9, 2.4 and 0.9 kbp for trisegmented genomes. The electrophoretic migration profile has considerable heterogeneity. PVBs are detected in diarrhoeic as well as non-diarrhoeic animals, hence, their potential needs further investigation.