Abhilasha Gupta (37), defeated her nearest rival Kamla Singh of the BJP by a comprehensive margin of more than 20,000 votes.
Altogether 29 candidates were in the fray for the Mayoral election.
The post of Mayor was reserved for women in the city in the ongoing local body elections.
Earlier, the post of city Mayor was held by Chaudhary Jitendra Nath Singh of the Congress.
This is the first time that a candidate associated with the BSP has been elected to the post.
Abhilasha Gupta had contested as an independent candidate in view of the BSP's decision not to allow its members to contest the local body polls without them being declared as official nominees or being allotted party symbols.
Abhilasha Gupta's husband Nandi, who was a cabinet minister in the previous Mayawati government in the state, had lost the assembly elections from Allahabad (South) seat held earlier this year, which also saw the BSP being voted out of power.