Kosgei became the Kenyan champion over 10,000 m that summer, and his next test came at the 2002 Commonwealth Games in Manchester, England. He was entered into the 10,000 m race and was second behind his Kenyan compatriot Wilberforce Talel – Kosgei's finishing time of 27:45.46 was seven hundredths of a second behind Talel, who broke the Games record for the event.
Kosgei won the Kenyan title in the 10,000 meters that summer and then competed at the 2002 Commonwealth Games in Manchester, England. He finished second to his teammate Wilberforce Talel in the 10,000-meter race, with Kosgei's time of 27:45.46 just behind Talel's record-breaking performance.