Capillary ultrafiltration membranes based on polysulfone and tin hydroxo compounds have been prepared by the phase inversion method. The formation of colloidal particles of tin hydroxo compounds in the membrane matrix has been carried out during the membrane formation process by hydrolysis of tin(II) chloride dihydrate, a component of the forming solution, in contact with the inner coagulating agent (water). The morphology and transport properties of the polymer-inorganic membranes have been studied. By using a digital image analysis program, it has been found that the addition of tin(II) chloride dihydrate to the forming solution increases the porosity, decreases the average pore size, and narrows the pore size distribution in the selective layer of the membrane. It has been revealed that the polymer-inorganic membranes are characterized by higher productivity and a lower retention compared with the unmodified membranes.