Mr Yadav first cast his vote for Sangma but "by mistake". However, he quickly rectified his mistake. He asked for a new ballot paper and again cast his vote for Pranab Mukherjee.
The Samajwadi Party supremo declared his support for UPA's choice Pranab Mukherjee. This was the second time when Mr Singh shocked all with his move regarding the presidential poll.
Earlier, Mr Singh along with Trinamool Congress chief and West Bengal Chief Minister Mamata Banerjee shook UPA after proposing Abdul Kalam, Manmohan Singh and Somnath Chatterjee's names instead of showing support for Pranab.
However, within forty two hours, he flipped from his earlier proposal and left Mamata in isolation. Completely changing his statement, Mulayam Singh announced that he wanted to go with UPA's choice.
On Thursday, once again Mulayam made the goof up, though it was a "mistake". The voting for the 13th President of India started at 10 am in New Delhi. The voting was simultaneously taking place at the national and state capitals and thousands of MPs and MLAs (776 and 4,120, respectively) were seen casting their votes.
Meanwhile, another shocking news surfaced after Gujarat BJP MLA Kanu Kalasariya decided to go against his party's decision and cast his vote in favour of Pranab and not for Sangma.
Meanwhile, Raj Thackeray's Maharashtra Navnirman Sena (MNS), which has 12 MLAs, has decided to abstain from voting. The voting will end at 5 pm.