ArachnoServer is a manually curated database containing information on the sequence, three-dimensional structure, and biological activity of protein toxins derived from spider venom. Spiders are the largest group of venomous animals and they are predicted to contain by far the largest number of pharmacologically active peptide toxins (Escoubas et al., 2006). ArachnoServer has been custom-built so that a wide range of biological scientists, including neuroscientists, pharmacologists, and toxinologists, can readily access key data relevant to their discipline without being overwhelmed by extraneous information.