Drug-loaded microspheres prepared from biomacromolecules have received considerable interest. In this article, we report a facile method for preparing ceftiofur-loaded gelatin-based microspheres for controlled release. We investigated the effects of factors, including the rotational speed, concentration of surfactant, concentration of gelatin, and ratio of water to oil (W/O), on the morphologies of gelatin microspheres and obtained the optimized conditions; for a typical average diameter of about 15 m, these were 1000 rpm, a concentration of span 80 of 2.0%, a gelatin concentration of 20%, and a W/O of 1:20. Gelatin microspheres loaded with ceftiofur, ceftiofur-Na, and ceftiofur-HCl were prepared and characterized by scanning electron microscopy and laser light scattering. In vitro release studies were carefully performed for microspheres prepared with different crosslinker contents, loaded with different drugs, and blended with chitosan. The loaded ceftiofur showed an obviously longer release time compared with pure ceftiofur powder. A higher content of crosslinker led to a longer release time, but when the content reached 5%, the microspheres had a significantly cracked surface. The results also indicate that the blending of a small amount of chitosan could greatly prolong the release time. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2369-2376, 2013