Induction of genes and proteins after DNA damaging treatment is well documented in various biological systems. In order to monitor repair activity in Schizosacchromyces pombe, we adapted the biochemical assay that allowed specific quantification of excision repair in mammalian cells (Wood et al. 1988, Cell, 53, 97-106) to yeast-free extracts. Repair synthesis determined on UV-damaged plasmid DNA with S. pombe total protein extract relied on base excision repair and not nucleotide excision repair. Under conditions that allowed optimal repair activity, an enhanced repair synthesis was found with extract from yeast previously irradiated with UV light (254 nm). A 4-fold induction factor was obtained with 70 J/m2 irradiation dose after 40 min incubation post-irradiation. This base excision repair activity on UV photoproducts was transiently induced since it returned to the level of untreated yeast after about 2 hours post-irradiation.