Abstract: A protective cover or boot for a keyboard array is provided which prevents entry of contaminants, such as water, dust and the like into the interior of the keyboard assembly. A membrane of a resilient material, such as a silicone rubber, is used to form a one-piece cover which extends over the keyboard array as well as the obverse face of the keyboard assembly and, in cooperation with a plate, acts as a seal to totally encapsulate the keyboard assembly. The elastomeric cover is formed as a low-cost material of generally uniform thickness and is molded to a shape so as to cover the top portion of the individual keys as well as extend partially down the side walls thereof so as to be spaced from the deck of the keyboard assembly by a distance which is equal to or greater than the length of travel of the key when actuated.