Xanthan gum (XG) was derivatized to sodium carboxymethyl xanthan gum (SCMXG) and then cross-linked with aluminium ions (Al+3) to prepare BSA-loaded microparticles (MPs) from a completely aqueous environment. The derivatized gum was characterized by various physical methods. Discrete and spherical BSA-loaded MPs were obtained from SCMXG solution, the pH of which was adjusted to 6 and 7 and the BSA entrapment efficiency was found to reach as high as 82%. The protein release in acidic dissolution medium was faster than that in alkaline dissolution medium and was accounted for the higher swelling ratio of the MPs in acidic environment. Moreover, the pH of the gum solution used to prepare the MPs also influenced the swelling and consequently protein release considerably.