The 1958 U.S. National Championships (now known as the US Open) was a tennis tournament that took place on the outdoor grass courts at the West Side Tennis Club, Forest Hills in New York City, United States. The tournament ran from 29 August until 7 September. It was the 78th staging of the U.S. National Championships, and the fourth Grand Slam tennis event of the year.

Finals

Men's singles

🇦🇺 Ashley Cooper defeated 🇦🇺 Malcolm Anderson 6–2, 3–6, 4–6, 10–8, 8–6

Women's singles

🇺🇸 Althea Gibson defeated 🇺🇸 Darlene Hard 3–6, 6–1, 6–2

Men's doubles

🇺🇸 Alex Olmedo (USA) / 🇺🇸 Ham Richardson (USA) defeated 🇺🇸 Sam Giammalva (USA) / 🇺🇸 Barry MacKay (USA) 3–6, 6–3, 6–4, 6–4

Women's doubles

🇺🇸 Jeanne Arth (USA) / 🇺🇸 Darlene Hard (USA) defeated 🇺🇸 Althea Gibson (USA) / 🇧🇷 Maria Bueno (BRA) 2–6, 6–3, 6–4

Mixed doubles

🇺🇸 Margaret Osborne (USA) / 🇦🇺 Neale Fraser (AUS) defeated 🇧🇷 Maria Bueno (BRA) / 🇺🇸 Alex Olmedo (USA) 6–4, 3–6, 9–7