Optical absorption and emission intensities of Er3+ ions in YAl3(BO3)(4) crystal have been investigated. It results in a good fit on absorption of the crystal, when the Judd-Ofelt theory of parity-forbidden electric-dipole transitions of rare earth ions on non-centrosymmetric sites is applied to Er:YAl3 (BO3)(4) (EYAB). Based on the Judd-Ofelt theory, the following spectral parameters have been obtained: intensity parameters Omega(1), Omega(2) = 6.54 x 10(-20) cm(2), Omega(4) = 1.89 x 10(-20) cm(2), and Omega(6) = 1.81 x 10(-20) cm(2), radiative transition probabilities A(J,J'), oscillator strengths P-J,P-J'. The radiative lifetime of levels I-4(11/2), H-4(9/2), and S-4(3/2) are 3.105, 0.213, and 0.297 ms, respectively. The fluorescence branching ratios for the transition S-4(3/2) --> I-4(15/2) is 81.0%. The value of integrated emission cross sections are also calculated. The emission transitions I-4(13/2) --> I-4(15/2), I-4(11/2) --> I-4(13/2), and S-4(3/2) --> I-4(15/2) provide potential applications of Er:YAl3(BO3)(4) as a laser material. (C) 2002 Published by Elsevier Science B.V.