The 12th season of "Gunsmoke" is not available on DVD, as of July 2015. Seasons one through 11 are available to purchase on DVD at Amazon.com.
DVDs of seasons one through 11 of "Gunsmoke" can be purchased on Amazon.com by navigating to the home page and entering "Gunsmoke" in the search bar. Seasons that are available for purchase are displayed on the next page. Amazon.com offers customers options to buy new or used DVDs of "Gunsmoke." Clicking on the title of individual seasons displays a description and reviews.
The first episode of "Gunsmoke" season 12 aired on Sept. 17, 1966 and the last episode aired on April 15, 1967.