The complete DNA sequence of equine herpesvirus-4 (EHV-4) strain NS80567 was determined. The genome is 145597 bp in size and consists of a long unique region (UL, 112398 bp) flanked by a short inverted repeat (TRL/IRL, 27 bp) linked to a short unique region (Us, 12789 bp) flanked by a substantial inverted repeat (TRs/IRs, 10178 bp). EHV-4 is predicted to contain 76 different genes; three of these are present twice in TRs/IRs, giving a total of 79 genes. The closely related virus equine herpesvirus-1 (EHV-1) also possesses 76 different genes corresponding to those of EHV-4, but has a total of 80 genes because four are present twice in TRs/IRs. Interpretations of the coding capacity of the EHV-4 and EHV-1 genomes were refined by comparing the complete DNA sequences.