Sm:YAl3(BO3)(4) crystal of good optical quality has been grown by the fluxed method. X-ray diffraction experiment show that the crystal has the same structure as that of YAl3(BO3)(4) Crystal and its unit cell constants have been Measured to be a = 9.28954 Angstrom, c = 7.24132 Angstrom. vol = 541.17 Angstrom(3). The thermal properties of Sm:YAl3(BO3)(4) crystal have been studied For the first time. The average thermal expansion coefficients are determined to be 2 x 10(-6)/degreesC, 9.5 x 10(-6)/degreesC along, a- and c-direction. The specific beat of the crystal has been measured to be 0.71 J/g degreesC at room temperature. (C) 2004 Elsevier B.V. All rights reserved.