The enzyme omega-transaminase catalyses the conversion of chiral omega-amines to ketones. The recombinant enzyme from Chromobacterium violaceum has been purified to homogeneity. The enzyme was crystallized from PEG 4000 using the microbatch method. Data were collected to 1.7 A resolution from a crystal belonging to the triclinic space group P1, with unit-cell parameters a = 58.9, b = 61.9, c = 63.9 A, alpha = 71.9, beta = 87.0, gamma = 74.6 degrees . Data were also collected to 1.95 A from a second triclinic crystal form. The structure has been solved using the molecular-replacement method.