Jeptoo tested positive for the blood-booster EPO in an out-of-competition test last September, a few weeks before winning her second straight Chicago Marathon title. Both the "A'' and "B'' samples were positive.
Athletics Kenya announced Friday that Jeptoo was suspended from all competition until Oct. 29, 2016. The sanction rules her out of this year's world championships in Beijing and next year's OIympics in Rio de Janeiro.
The 33-year-old Jeptoo is the biggest name among dozens of Kenyan athletes who have failed drug tests in recent years. The World Anti-Doping Agency has urged Kenya to step up its drug-testing program and is working with the east African country to help set up a national anti-doping body.
Jeptoo appeared at a disciplinary hearing in Nairobi earlier this month. Also testifying were her estranged partner, Noah Busiendich, Italian manager Federico Rosa and Italian coach Claudio Berardelli.
"For now, the case of Rita has come to a rest and what remains now for us is to move on," Athletics Kenya president Isaiah Kiplagat told The Associated Press. "We shall see how we shall work with the new anti-doping agency of Kenya in partnership to deal with the vice."
Jeptoo has already been denied her share of the $500,000 prize for winning the 2013/14 World Marathon Majors.
'"Her positive test has made it very difficult for us," two-time women's marathon world champion Edna Kiplagat said. "We keep on being asked about doping every time we go to compete out there and I'm hoping that her punishment will make others stop engaging in this bad thing."
"I hope the (ban) will deter Kenyan athletes to stop taking short cuts," added Kiplagat, who stands to be upgraded to winner of the World Marathon Majors. "It will be a lesson for others. It's unfortunate since nobody wants anyone to be banned. If you take something like EPO which is injected as a professional athlete, it is obvious you know what you are putting in your body."
Kenya has been under close scrutiny since German broadcaster ARD alleged in 2012 that doping was common among the country's distance runners.
Kiplagat said this month that Athletics Kenya has banned or suspended 32 athletes for doping in the past five years.
"Our athletes should work hard to ensure we don't bring down what has taken 50 years to build," the 2008 Olympic men's 800-meter champion Wilfred Bungei told the AP on Friday.
Anti-doping bodies from Norway and China are helping Kenya set up its own anti-doping agency.
Boston Marathon organizers said they would evaluate Jeptoo's ban before making any decision on stripping her results in the race.
"We are deeply disappointed in the findings involving Rita Jeptoo, and we are committed to upholding the integrity and credibility of the Boston Marathon," Tom Grilk, executive director of the Boston Athletic Association, said in a statement.
The World Marathon Majors said the winner of the 2013/14 prize would not be determined until the completion of due process in Jeptoo's case and the outcome of any appeal. Under WMM rules, any athlete sanctioned for doping is ineligible to win the series title.