Dekum Building, historic office building in downtown Portland, Oregon, U.S.

The Dekum Building is a commercial structure in Portland featuring a sturdy base of large sandstone blocks and brick upper floors, designed in the Romanesque Revival style. Oversized arches and detailed carved decorations across the facade demonstrate the craftsmanship typical of late 19th-century construction.

Completed in 1892 by architects McCaw, Martin and White, the Dekum Building cost US$300,000, equivalent to about $9.3 million in 2024. It was named for Frank Dekum, a German immigrant who opened Portland's first candy shop and lived 1823–1894. It joined the National Register of Historic Places in 1980.

The building is named after Frank Dekum, a German immigrant who opened Portland's first candy shop. Its design is credited to the firm McCaw, Martin and White. During construction, masons reportedly drank beer instead of the usual coffee, an anecdote that survives from the 1891–1892 building campaign.

The building is located in central Portland and is easily accessible on foot, particularly when exploring the historic downtown area. The surrounding neighborhood offers other historic sites and small shops to visit.

Frank Dekum insisted that only Oregon materials be used in the building's construction, reflecting his pride in local resources and connection to the region. This commitment to local sourcing was unusual for a major commercial building of that era.