In this study, we have calculated the oscillator strengths for intersubband electronic transitions associated with an on-center impurity in a spherical quantum dot. Numerical calculations have been performed for both infinite confinement case and for different finite confining potential values in a spherical CdS/SiO2 quantum dot. Also, for comparison purpose, oscillator strengths for a spherical ZnS/SiO2 quantum dot with an infinite confinement potential are evaluated. © 2006 Elsevier B.V. All rights reserved.