Poly(vinyl alcohol)-guar gum interpenetrating network microspheres were prepared by cross-linking with glutaraldehyde. Nifedipine, an antihypertesive drug, was loaded into these matrices before and after cross-linking to study its release patterns. The extent of cross-linking was analyzed by Fourier transform infrared spectroscopy and differential scanning calorimetry. Furthermore, the microspheres were characterized for drug entrapment efficiency, particle size, transport of water into the matrix and drug release kinetics. Scanning electron microscopic photographs confirmed the spherical nature and surface morphology. The mean particle size of the microspheres was found to be around 300μm. The molecular transport phenomenon, as studied by the dynamic swelling experiments, indicated that an increase in cross-linking affected the transport mechanism from Fickian to non-Fickian. Thein vitrorelease study indicated that the release from these microspheres is not only dependent upon the extent of cross-linking, but also on the amount of the drug loaded as well as the method of drug loading.