We have determined the complete genomic sequence of human astrovirus serotype 1 isolated in Newcastle upon Tyne. The genome is 6813 nucleotides long and contains three sequential open reading frames (ORFs). The two closest to the 5' end are linked by a ribosomal frameshifting motif and contain sequence motifs indicative of non-structural virus proteins: serine protease and RNA-dependent RNA polymerase. A nuclear addressing sequence is also located here. The 3' ORF encodes the virion structural polypeptides as a polyprotein precursor. This genomic organization resembles that of the plant virus family Luteoviridae.