Numerous proteins contain domains that are enriched in glutamine and asparagine residues, and aggregation of some of these proteins has been linked to both prion formation in yeast and a number of human diseases. Unfortunately, predicting whether a given glutamine/asparagine-rich protein will aggregate has proven difficult. Here we describe a recently developed algorithm designed to predict the aggregation propensity of glutamine/asparagine-rich proteins. We discuss the basis for the algorithm, its limitations, and usage of recently developed online and downloadable versions of the algorithm.