Absorption spectra, fluorescence spectra and fluorescence decay curves have been measured at room temperature. Spectroscopic and laser performance parameters of Yb3+ in bismuth borate glasses with different compositions and Yb3+ concentrations were calculated. The effects of the host glasses compositions and Yb3+ concentration on the spectroscopic and laser performance parameters have been analyzed. The effect of radiation trapping on the spectroscopic properties has also been discussed. The results show that the Yb3+-doped bismuth borate glass is a promising laser material. (C) 2003 Published by Elsevier B.V.