Sequence comparisons between human and rodents are increasingly being used for the identification of gene regulatory regions. The effectiveness of such an approach largely depends on the quality and availability of promoter sequences. We developed OMGProm by integrating three data sources: (1) experimentally supported full-length cDNA, promoter and first exon sequences, (2) homology information from HomoloGene and (3) the human and mouse genomic sequences. The current version of OMGProm contains 8550 promoter pairs of 6373 orthologous human and mouse genes, where supporting experimental evidence for transcription start site annotation exists in at least one species.