A zipper added to the pocket on a pair of pants can be for functionality, fashion or both. Adding a zipper allows the pocket to be sealed shut so that it securely holds small items. A zipper is a fast and easy way to alter the style of a pair of pants or enhance the look of the pocket. Regardless of the reason, adding a zipper to a pants pocket is a simple task that can be performed by following some basic sewing techniques.

Clean your work surface with a damp cloth to remove any dust or dirt. Place your sewing supplies on the work surface. Lay the pants down horizontally on the surface. Separate the zipper into two pieces.

Open the pants pocket as wide as it will go. Place one piece of the zipper on the pants. Position the zipper so that the end of it extends 1/2 inch past where the opening in the pocket begins. Pin the zipper in place. Place the other zipper piece on top of the pocket. Line the two piece up so that they are even. Pin in place.

Place the zipper pull at one end of the pocket. Sew the zipper onto the pants using a basic sewing technique. Pay extra attention to the ends of the zipper and add double stitching to reinforce. Remove the sewing pins as you go. Sew the other piece of zipper onto the pocket in the same way.

Pull the zipper pull up and down several times to make sure the zipper is firmly attached to the pants and pocket. Check to see if the zipper feels loose and restitch as necessary.