Remove the old cushions from the chair. Untie any straps used to keep the cushions in place.
Remove the cushion padding from the original cover. Use a seam ripper to carefully tear along the seams of the cushions to remove the padding.
Lay the original cushion cover on top of the new fabric. The old fabric will serve as the pattern for the new covers.
Cut the fabric for the new cushion covers. Use straight pins to secure each piece of old fabric to the new fabric before cutting the cushion pattern out of each piece.
Mark and pin the pleats. With the original fabric still on top of the new fabric, examine the original cushion cover, and notice if there are pleats in any of the corners. Mark the pleats with a fabric pen on the new fabric, and then pin all pleats in place.
Sew the pieces together. Lay the two pieces of fabric used to make one cushion cover on top of each other, pattern-side facing each other. Match any pleats before pinning around three sides of the cover. Leave the back of the cover open to reinsert the cushion. Use a straight stitch to sew around the cover, removing pins along the way.
Turn the cushion cover right-side out and insert the cushion. Turn the edges inward on the open side of the fabric and use straight pins to hold them together. Use a blind stitch to close the fabric.
Repeat for each cushion on the chair.