His focus of the 2010 season was to retain his world title at the 2010 IAAF World Indoor Championships. In the buildup to the competition, he ran at the Aviva Indoor Grand Prix in Birmingham and improved his 1500 m indoor best to 3:33.10 – fifth on the all-time rankings. At the World Indoor Championships Mekonnen held off a challenge from Abdalaati Iguider and became the first athlete since Hicham El Guerrouj to win back-to-back 1500 m titles indoors. A stomach problem side-lined him for six months but on his return in January 2011 he broke Bernard Lagat's six-year-long win streak in the Wanamaker Mile at the Millrose Games.