The genome of stomatitis papulosa virus (a parapoxvirus) was cleaved with the restriction endonucleases HindIII and EcoRI, each giving rise to 6 fragments respectively. Double digestion with both enzymes resulted in 8 bands, two of which contained DNA fragments in double molar concentrations as revealed by reciprocal digests of isolated DNA fragments. The genome size, estimated by summation of the molecular weights of the fragments, is approximately 86 X 10(6) daltons, some 30 X 10(6) daltons smaller than vaccinia virus (an orthopoxvirus) DNA. The cleavage sites of HindIII and EcoRI endonucleases were mapped on the genome by analysis of reciprocal digests of isolated DNA fragments and by cross-hybridization experiments. This yielded two mapped segments which were then oriented relative to one another by cleavage of isolated partial digestion products. The terminal restriction fragments show rapid renaturation after alkali denaturation and subsequent neutralization, indicating that stomatitis papulosa virus DNA contains terminal cross-links analogous to those found in vaccinia virus DNA.