As of 2015, a good location to purchase replacement rollers for a sliding door is Lowe's. This home improvement store carries a variety of replacement parts for sliding doors.
Replacement rollers may be purchased at Lowe's online or in store. The store finder on the website can be used to find the nearest retail location.
Another good location for finding sliding door parts is Home Depot. Orders can be placed online and picked up in a local store. Customers can sign up for a free newsletter to receive promotional deal, sales and special offers via email.
Custom Service Hardware is an additional resource for parts. Parts for doors, kitchen cabinets and drawers, furniture and lighting are also available for sale.