This document describes a new approach to predict protein function in humans by combining large-scale evolutionary analyses with multiple biological data sources. The approach uses 49,231 features derived from sources like sequence similarity, predicted structural characteristics, domain architectures, gene fusions, gene co-expression, and protein-protein interactions to compute a functional similarity score between proteins. This functional similarity score is then used to predict Gene Ontology terms and annotate unannotated human protein sequences. The approach was able to annotate 30% of previously unannotated human protein sequences.