Deficiency in a helicase of the RecQ family is found in at least three human genetic disorders associated with cancer predisposition and/or premature ageing. The RecQ helicases encoded by the BLM, WRN and RECQ4 genes are defective in Bloom's, Werner's and Rothmund-Thomson syndromes, respectively. Cells derived from individuals with these disorders in each case show inherent genomic instability. Recent studies have demonstrated direct interactions between these RecQ helicases and human nuclear proteins required for several aspects of chromosome maintenance, including p53, BRCA1, topoisomerase III, replication protein A and DNA polymerase delta. Here, we review this network of protein interactions, and the clues that they present regarding the potential roles of RecQ family members in DNA repair, replication and/or recombination pathways.