The influence of poly(ethylene glycol) (PEG) and synthesis temperature in the synthesis of SBA-15-SO3H was investigated to evaluate the catalytic activity in the esterification of propionic acid with methanol. The catalysts were characterized by means of surface and structure analyses; X-ray diffraction, FT-IR, scanning electron microscopy, Thermo-gravimetric and N-2 adsorption/desorption techniques. It was found that, by the addition of PEG, the surface area and porosity of SBA-15-SO3H increased, while the structure and size of mesopores remained unchanged. Nitrogen sorption measurements indicate that PEG introduces additional pores into the pore walls of SBA-15-SO3H. Thus, a simple way of improving the porosity of mesoporous SBA-15-SO3H was presented that could enhance transport of substrates through the porous system and allow the generation of stable mesoporous replicas, important for catalytic applications and also beneficial for replication and nanocasting purposes.