Registration for the marathon is still open online until 17.00 on 24 October.
The annual event, sponsored by Standard Chartered for the 12th year running, includes not just the usual full (42 km) and half marathons (21 km) but also tricycles (42 km) and wheelchairs (21 km).
There is also a 10 km course and a family (5 km) event. The courses start and end at the Nyayo Stadium.
This year the Standard Chartered is hoping for some 25,000 participants. Money raised from the event will be donated to Seeing is Believing to eradicate avoidable and curable blindness.
There are about 300,000 blind people in Kenya, 14,000 of them children. The marathon raised KSh 23 million in 2013, KSh 2 million more than the previous year.