The expression of an exotoxin called cytolysin contributes to the virulence of Enterococcus faecalis, one of the organisms responsible for antibiotic resistant infections acquired in hospitals. The DNA-binding protein CylR2 is a transcriptional repressor of cytolysin. At a specific cell density, cytolysin triggers signaling events, which result in the dissociation of CylR2 from its DNA-binding site. CylR2 was overexpressed in Escherichia coli and purified and crystals diffracting to 1.9 A were obtained in two different crystal forms. One crystal form belongs to space group P4(1), with unit-cell parameters a = 63.7, b = 63.7, c = 41.2 A, alpha = beta = gamma = 90 degrees, and the other belongs to space group P1, with unit-cell parameters a = 36.9, b = 45.0, c = 47.7 A, alpha = 67, beta = 90, gamma = 66 degrees.