Purses can be expensive, so don't discard a favorite -- or pass up a thrift-store bargain -- because of a separated strap. The friction of a shoulder or hand rubbing on your bag's strap often causes the stitching to wear and the layers of leather to separate. Thankfully, you can fix any separated leather item.
Take your strap and cut off the loose stitching back to the good portion. Remove all loose thread. You should be left with two layers of strap with tiny holes for stitching.
Thread your needle. The needle should be sharp and small enough to fit easily through the holes and the thread should be similar to that used in the rest of the bag.
Secure your thread by tying a small knot in the end. Open up a space between the layers of the strap. Squeeze a dot of glue between the layers. Insert your needle into the last "good" stitch going from space between the layers and up through the top -- pull through to the knot and press the layers closed.
Sew your first pass. Bring your needle down into the next hole, through both layers, then up through the next hole. Repeat until you have inserted the needle into the first "good" stitch on the other side of the worn area. Make sure you pull your thread tight after each stitch.
Retrace your steps. When you're done your first pass, it will look like you have done every-other stitch. Now you will sew in the other direction to complete the stitching. Repeat step 4 going in the opposite direction, making sure that your thread finishes on the bottom of the strap.
Finish it off. To make a knot, pass your needle through the thread of the stitch you just made -- just the thread, not the hole in the leather -- and pull your thread until there is just a small loop. Pass your needle through the loop two to three times and pull it down tight to form the knot. Apply a small dot of clear nail polish to the knot to prevent it from coming undone and let dry.