The tallest man ever (recorded and verified) was Robert Pershing Wadlow (22 Feb 1918 – 15 Jul 1940). He reached 8 feet 11.1 inches 2 m 72 cm in height. His weight was 490 pounds (220 kg).

His great size and his continued growth in adulthood was due to hypertrophy of his pituitary gland which results in an abnormally high level of human growth hormone. He showed no indication of an end to his growth even at the time of his death. Source: wikipedia.org

The tallest living man is mongolian Bao Xishun (Xi Shun, The Mast). Bao was born in 1951 in inner Mongolia (China). He measures 7 feet 8.91 inches (2 m 36 cm) tall.

Tallest people list: wikipedia.org
John Rogan – Second tallest male in recorded history at 8’9 ½” (268 cm). Tallest African American. (b.1868, d.1905)
Don Koehler – 8′ 2″ (2.49 m), Tallest in World for most of 1970s. Had 5’10” twin sister. (September 1, 1925 – February 26, 1981)
Zhao Liang – 8′ 1.1″ (2.48 m)
Väinö Myllyrinne – Tallest Finn, standing 8’1″ (247 cm). Myllyrinne was born in 1909 and died April 13, 1963.
Gabriel Estêvão Monjane – Guinness World Records listed him as tallest man from 1988 to 1990 at 8’1″ (246 cm). (b.1944, d.1990)

Talles female list:
Trijntje Keever – Tallest recorded woman at 8’4″ (254 cm). Died in 1633 at age 17.
Zeng Jinlian – Tallest woman at 8’2.75″ (249 cm). Suffered from spine curvature and could not stand at full height. Died in 1982 at age 17.
Jane Bunford – Former world’s tallest woman (until Zeng Jinlian) and possibly the world’s tallest person at the time of her death in April 1922 at 7’8″ (234 cm), but due to a curved spine she could not stand up straight. However, if her spine had normal curvature, she would have stood 8’0 (244 cm).
Yao Defen – Claimant as tallest living female at 7’9″ (234 cm). Not confirmed by Guinness World Records.
Sandy Allen – Listed as tallest living female by Guinness World Records at 7’7¼” (232 cm), until her death on August 13, 2008.

See also:
Length converter