Magnetic nanoparticles (MNPs) are considered as ideal supports for the heterogenization of homogeneous catalysts, since they can be recovered by using an external magnet and reused for several time without significant loss of their catalytic efficiency [1]. The acylation of alcohols is one of the most frequently used transformations in organic synthesis, as it provides an efficient and inexpensive means for protecting hydroxy groups in a multistep synthetic process [2]. In continuation of our systematic studies about application of magnetic nanocatalysts in organic synthesis [3], herein, we prepared magnetic nanoparticles supported silica sulfuric acid (MNPsSSA) according to Scheme 1. The MNPsSSA was characterized with TGA, SEM, XRD and FTIR techniques and was used as a novel, efficient and reusable nanocatalyst for the acetylation of alcohols and phenols with acetic anhydride at room temperature under solventfree conditions