The Kenyan defended his 2017 title in the German capital, pulling ahead of other runners early on amid perfect conditions.
Mild temperatures and little to no wind gave the runners of the 45th Berlin marathon an advantage over last year, when rain slowed the race.
Berlin debutant Amos Kipruto came second in 2h 06m 23s, followed by a third Kenyan, former world-record holder Wilson Kipsang, with 2h 06m 48s.
Gladys Cherono won the women's race in 2h 18m 11s, a record for the Berlin marathon. The previous record was set by Mizuki Noguchi of Japan 13 years ago. The 35-year-old Kenyan, who has won twice before in Berlin, said she felt confident going into the race but wasn't sure she would beat favourite Tirunesh Dibaba, who came third behind fellow Ethiopian Rutia Aga.
A total of 44,389 runners from 133 countries took part in the race.
- AP