A novel cyan fluorescent protein, dsFP483 from the coral Discosoma striata, has been crystallized. Diffraction data were collected to 2.1 A and processed in space group C2. Molecular-replacement methods were applied using the closely related red fluorescent protein DsRed as a search model. The asymmetric unit appears to contain six protein molecules (1.5 tetramers), five of which (83%) could be located by the molecular-replacement searches.