The treasure trove of personal stuff includes scripts from the original Dallas TV series, J.R. Ewing's cowboy boots and memorabilia from his other TV hits I Dream of Jeannie, Bewitched and My Favorite Martian.
Hagman is also putting personal antiques, fine and decorative art and furniture up for sale - and there will also be items he collected from his actress mother Mary Martin's career.
The sale, to be held at the prestigious Julien's Auctions Gallery in Beverly Hills, will take place on 4 June (11).
All the items were stored at Hagman's hilltop estate Heaven, which he built in 1991.
Among the art pieces is an 18th century Spanish Colonial painting of the Madonna and Child and works by Barton Benes and Bruce Killen, while the antiques include an Italian credenza, a Rosewood Regency drop leaf table and a set of 10 Chippendale-style dining chairs with needlepoint upholstery.
Also up for grabs are a custom-made mounted parade saddle, a pair of monogrammed boots Hagman wore as Ewing in Dallas, and items from his collection of guns and knives.