SummaryTransfer of buddingCandida albicansyeast cells from the rich, complex medium YEPD to the defined tissue culture medium RPMl 1640 (RPMI) at 37°C and 5% CO2causes rapid onset of hyphal induction. Among the genes induced under these conditions are hyphal‐specific genes as well as genes expressed in response to changes in temperature, CO2and specific media components. A cDNA library constructed from cells incubated for 20 min in RPMI was differentially screened with yeast (YEPD)‐ and hyphal (RPMI)‐specific probes resuming in identification of a gene expressed in response to culture conditions but not regulated by the yeast‐hyphal transition. The deduced gene product displays significant identity toSaccharomyces cerevisiaeα‐agglutinin, encoded byAGα1, an adhesion glycoprotein that mediates mating of haploid cells. The presence of this gene inC albicansis curious since the organism has not been observed to undergo meiosis. We designate theC. albicansgeneALS1(foragglutinin‐likesequence). While theN‐and C‐termini of the predicted 1260‐amino‐acid ALS1 protein resemble those of the 650‐amino‐acid AGα1, ALS1 contains a central domain of tandem repeats consisting of a highly conserved 36‐amino‐acid sequence not present in AGb1. These repeats are also present on the nucleotide level as a highly conserved 108bp motif. Southern and Northern blot analyses indicate a family ofC. albicansgenes that contain the tandem repeat motif; at least one gene in addition to ALS1 is expressed under conditions similar to those for ALS1 expression. Genomic Southern blots from severalC. albicansisolates indicate that the number of copies of the tandem repeat element in ALS1 differs across strains and. In some cases, between ALS1 alleles in the same strain, suggesting a strain‐dependent variability in ALS1 protein size. Potential roles f