Calcium pyromobate (Ca2Nb2O7) has been discovered as a new nonlinear optical crystal by the Kurtz power method, and the intensity of second harmonic of a Nd:YAG laser generated by this crystal is 5.2 times that of KDP crystal. Following this discovery, attempts to obtain large Ca2Nb2O7 single crystals of improved optical quality have been undertaken. A reasonably good quality crystal of 25 mm diameter and 35 mm length has been grown by the Czochralski method. Its optical transparency range has been measured and found to span from 370 to 5500 run. (c) 2004 Elsevier B.V. All rights reserved.