Recent years have seen an explosion in the availability of protozoan pathogen genome sequences. Although data regarding the underlying genome sequence remain relatively stable after the initial draft, understanding of specific gene function is increasing rapidly. This dichotomy is reflected in the relative stability of systematic gene identifiers (SysIDs(*)) in genome sequence databases, as compared to evolving and/or conflicting gene and gene product names. GenBank/EMBL/DDBJ accession numbers are important, but most protozoan parasite researchers use organism-based databases such as EuPathDB or GeneDB as their immediate resource for gene-based information because they not only provide sequence information but also functional information and links to references. Reference to SysIDs therefore provides a valuable bridge to this repository of information.