PubTator is an automated, web-based system that assists with biocuration by providing PubMed-like functionality along with text mining algorithms to improve the efficiency and accuracy of manual curation. It is publicly available at http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/PubTator/ and allows users to select documents, annotate texts with bioconcepts, establish biorelations between concepts, and download annotations. The system aims to help keep pace with the rapid growth of biomedical literature by facilitating the curation process.