ABSTRACTGenes encoding the TFIID TATA‐box binding protein (TBP) from two probable species of ratPneumocystis carinii(prototype and variant) were sequenced. The twoP. cariniiTBP gene sequences were 91% identical to each other, and 65‐77% identical to TBP genes from other species. A cDNA from one of the twoP. cariniiTBP genes was sequenced, which showed that four small introns resided in identical positions within the TBP genes from the prototype and variant ratP. carinii.Conservation of the 180 amino acids that constitute the conserved core of TBP was 97% between theP. cariniiTBP, which were 95% and 97% identical to conserved core sequences of TBP fromSaccharomyces cerevisiaeandSchizosaccharomyces pomberespectiv