Protein disulphide isomerase (PDI) catalyses the formation, reduction and isomerization of disulphide bonds in the newly synthesized secretory proteins. Plant PDIs have been shown to be involved in the folding and deposition of seed storage proteins, which makes this enzyme particularly interesting in wheat, as flour quality is strongly affected by composition and structure of seed storage proteins. In hexaploid wheat cultivar (AABBDD) Chinese Spring (CS), the genomic, complementary DNA and promoter sequences of the three homoeologous gene encoding PDI had been isolated and characterized in a previous study revealing high levels of sequence conservation. In this study, we report the isolation and sequencing of a 700 bp region, comprising 600 bp of the putative promoter region and 88 bp of the first exon of the typical PDI gene, in five accessions each from Triticum urartu (AA), Aegilops speltoides (BB) and Aegilops tauschii (DD). Sequence analysis indicated large variation among sequences belonging to the different genomes, while close similarity was found within each species and with the corresponding homoeologous PDI sequences of Triticum aestivum cv. CS (AABBDD) resulting in an overall high conservation of the regulatory motifs conferring endosperm-specific expression.