Moving into the senior ranks, at the 2006 World Cross Country Championships she finished twelfth in the long race, helping the Kenyans to the silver medal in the team competition. She was fifth in the steeplechase at both the 2007 All-Africa Games and 2008 African Championships in Athletics. Njoroge won the silver medal in the steeplechase behind Milcah Chemos Cheywa at the 2010 Commonwealth Games in New Delhi.