Previously, the sequence of the Schizosaccaromyces pombe cdc2 gene was reported to begin at a HindIII site, 141 nucleotides (nt) upstream from the ATG start codon [Hindley and Phear, Gene 31 (1984) 129-134]. We have extended the sequence of the 5' untranslated region of the gene to a PsI site at -822 nt. We demonstrate by primer extension analysis that transcription of the gene initiates at one major point 180 nt upstream from the ATG start codon. Since the 822-nt fragment extending from the PstI site to the start codon has been used in many studies as the promoter for cdc2 [Booher and Beach, Mol. Cell. Biol. 6 (1986) 3523-3530; Carr et al., Mol. Gen. Genet 218 (1989) 41-49; Gould and Nurse, Nature 342 (1989) 39-45], we investigated the strength of this promoter element relative to the SV40 early promoter, a promoter known to work very well in S. pombe [Jones et al., Cell 53 (1988) 659-667]. We confirm that the cdc2 gene fragment has significant promoting activity, albeit 20- to 60-fold less than the SV40 early promoter, when assayed in S. pombe.