Crystals of a 60-amino-acid C-terminal deletion mutant of the herpes simplex virus 1 single-stranded DNA binding protein, ICPS, have been grown by hanging drop vapor diffusion. The colorless crystals grow as thin plates to a maximum size of approximately 0.3 mm x 0.3 mm x 0.05 mm. The space group is P2(1)2(1)2(1) with unit cell constants a = 101.2 Angstrom, b = 145.8 Angstrom, and c = 162.9 Angstrom. There are one or two molecules of ICP8 per asymmetric unit.