Election Commission Secretary Helaluddin Ahmed announced the key deadlines for the July 30 polls on Wednesday noon.
Mayoral elections in the cities will be held on July 30, he said.
According to the election schedule announced, the last date for filing nomination is June 28 and withdrawing July 9.
The nomination papers will be scrutinized on July 1 and 2.
The tenures of three city corporations will expire by this October. The tenure of Rajshahi City Corporation will expire 5 October and Sylhet on 8 October and Barisal on 24 October.
The electoral law stipulates that the elections to the city corporations will be held within six months before the expiry of the local body.