Raila Odinga cites what he calls the government's failures in tackling the rise in violence, high cost of living and rampant corruption. He has said it is not a bid to unseat the government.
Aides to President Uhuru Kenyatta have dismissed the call for dialogue, saying there are already channels for debate, such as parliament. They have accused the former prime minister of trying to claw his way back to power.
The rally comes on the heels of a series of fatal attacks in many parts of the country. The most recent took place over the weekend in the coastal areas of Gamba and Hindi, in which 29 people were killed.
But that was not as bad as last month's attack in the same area, when gunmen opened fire in the town of Mpeketoni and killed 65 people.
So, will these sorts of rallies only fuel more chaos in Kenya? And who is to blame for the recurrent violence?
Presenter: Folly Bah Thibault
Abdullahi Boru Halakhe - Horn of Africa security analyst.
Dismas Mokua - political analyst and deputy president of Africa Axis, a consultancy advising companies on doing buisness in Africa.