In Brushaber v. Union Pacific Railroad Co., the Supreme Court of the United States declares the federal income tax constitutional.

Brushaber v. Union Pacific Railroad Co., 240 U.S. 1 (1916), was a landmark United States Supreme Court case in which the Court upheld the validity of a tax statute called the Revenue Act of 1913, also known as the Tariff Act, Ch. 16, 38 Stat. 166 (October 3, 1913), enacted pursuant to Article I, section 8, clause 1 of, and the Sixteenth Amendment to, the United States Constitution, allowing a federal income tax. The Sixteenth Amendment had been ratified earlier in 1913. The Revenue Act of 1913 imposed income taxes that were not apportioned among the states according to each state's population.