Ethyl silicate oligomers were impregnated into a generic Phillips Cr/silica catalyst used commercially for ethylene polymerization. After calcination, this treatment results in a secondary deposition of silica into the original silica matrix, which changes the porosity of the catalyst somewhat and strengthens its overall structure. The process can be used as a powerful tool to manipulate polymer properties because the molecular weight of the polymer, the MW distribution, and the amount of long-chain branching (LCB) it contains, were found to be strongly influenced, and with them all aspects of molding behavior. This result provides still more evidence that the physical structure of the Cr/silica catalyst can have major consequences for the polymerization reaction, which shapes the character of the polymer. This method of controlling polymer properties is perhaps more convenient for commercial operations than those described previously.