The student, whose name was not reported, was in her third year at the Krasnoyarsk State Medical University in Krasnoyarsk when she was allegedly expelled for wearing her hijab, which is a head scarf worn by some Muslim women, RIA Novosti reported.
Last week a local TV station reported the story, piquing the interest of prosecutors.
"After the TV report [about the incident] was broadcast, the Krasnoyarsk district prosecutors launched a probe to check the legitimacy of the expulsion," local prosecutor's aid Yelena Pimonenko told RIA Novosti on Monday.
The university said the woman was expelled for "violating internal regulations," but declined to give details.
School's rules issued in early February, which have been published on its website, say students are forbidden from wearing "items of clothing that stress their religious affiliation" on campus.