Janeth Jepkosgei Busienei (born December 13, 1983) is a Kenyan middle distance runner and former world champion.
Her breakthrough year was 2006. On March 24, 2006 she won the women’s 800 m event at the 2006 Commonwealth Games with a time of 1 minute, 57.88 seconds. She managed to beat veteran runner Maria de Lurdes Mutola of Mozambique. Later same year she won African Championships in Athletics at the 800 m event. She also beat Kenyan 800 m women’s record twice. Jepkosgei was awarded the 2006 Kenyan Sportswoman of the Year award.
Jepkosgei made Kenyan History on 28 August 2007, where she won gold in the World Championship 800 m final in Osaka, becoming the first female Kenyan middle distance runner to achieve gold over 800 m. She led from start to finish to win in a time of 1 minute, 56.04 seconds, beating the Kenyan record and world leading time (1.56,18) she had set at the heats two days earlier. She retained the Kenyan Sportswoman of the Year award.
On 24 May 2008 the 19-year-old Pamela Jelimo set a new Kenyan record of 1:55.76, beating the one previously held by Jepkosgei. Jelimo’s dominance throughout the season prevented Jepkosgei from major victories, but won Olympic silver medal over 800 m.