Er3+ /Yb3+-codoped Ca3Y2(BO3)(4) crystal with dimension O20 x 40 mm(3) has been grown by the Czochralski method. The absorption and emission spectra of Er3+/Yb3+ :Ca3Y2(BO3)(4) crystal have been investigated. The absorption band at 900-1050nm has an absorption coefficient of 12cm(-1) and FWHM of 8.5nm. A strong emission band at 1450-1650 nm due to the 4I(13/2) --> 4I(15/2) transition of Er3+ was observed. The fluorescence lifetime is about 3.29 ms. The process of energy transfer from the Yb3+ to the Er3+ was explained in Er3+ /Yb3+ :Ca3Y2(BO3)(4) crystal. (C) 2004 Elsevier B.V. All rights reserved.