CHICAGO – Two-time champion Berhane Adere will try to become the first woman to win three straight Chicago Marathon titles Sunday, with Olympic champion Constantina Tomescu-Dita among those out to prevent the three-peat.

Ethiopia’s Adere and Kenyan Daniel Njenga in the men’s race rounded out the elite field announced for Sunday’s race. Njenga has finished in the top three six times in Chicago, but will be seeking his first victory in the Windy City.

Njenga will have his work cut out if he is to end his run as Chicago’s nearly-man. Kenyan William Kipsang heads the field, having posted a course record of 2hr 05.49 in winning the Rotterdam Marathon in April.

Kenyan Emmanuel Mutai seemps poised to put some pressure on Kipsang, having finished fourth in the London Marathon in April with a personal best of 2:06.15. Adere will try to follow up on two dramatic Chicago victories. Last year she took Adriana Pirtea unawares, sprinting past the Romanian in the final meters.

In 2006, Adere and Russian Galina Bogomolova trailed Romania’s Tomescu-Dita, who had set a record pace through the first 16 miles. She was reeled in the 22nd mile of the 26.2 mile course, and Adere and Bogomolova battled shoulder to shoulder until the Ethiopian edged into the lead and won by five seconds.

This year, the 38-year-old Tomescu-Dita – who won on the fast, flat Chicago course in 2004 – arrives hot off an Olympic gold medal win in the women’s marathon in Beijing while her fellow Romanian Pirtea shaved five minutes off her marathon best with a 2:28:52 in London in April.

Tomescu-Dita’s feat in Beijing, where she became the oldest Olympic marathon gold medallist, has already inspired other athletes. Seven-time Tour de France champion Lance Armstrong cited her in his decision to return to road racing in 2009. Britain’s marathon world record-holder Paula Radcliffe, disappointed in the Games, has said she will try again in 2012, when she will be 38.

Njenga will be trying to break a Chicago jinx. He has finished second or third in each of his last six appearances, including a third-place showing last year behind the photo finish of Kenyan Patrick Ivuti and Morocco’s Jaouad Gharib.

Njenga has never lost to the same competitor twice – finishing behind a stellar roster of marathoners in Ivuti, Robert K. Cheruyiot, Felix Limo, Evans Rutto and Khalid Khannouchi. Njenga is one of six men in the field who have posted personal bests below 2:07:00.