Crystals of recombinant NovN, an O-carbamoyltransferase from Streptomyces spheroides, were grown by vapour diffusion. The protein crystallized in two different crystal forms. Crystal form I belonged to space group C2 and native data were collected to 2.9 A resolution in-house. Crystal form II had I-centred orthorhombic symmetry and native data were recorded to a resolution of 2.3 A at a synchrotron. NovN catalyses the final step in the biosynthesis of the aminocoumarin antibiotic novobiocin that targets the essential bacterial enzyme DNA gyrase.