77-year-old Mishra, who is survived by two daughters, was ill for a long time and died in hospital where he was admitted following complaints of chest pain last night.
He was being brought here for treatment as his condition deteriorated, SP spokesman Rajendra Chaudhary said.
Fondly called "Chotey Lohia" for his life-long association with the Samajwadi movement, Mishra was the leader of the Samajwadi Party in Rajya Sabha.
Despite bad health, Mishra had led the party's agitation against price rise and corruption in Allahabad on January 19.
He was elected to the Lok Sabha for the first time in 1977 from Allahabad and became Petroleum Minister in the Chandra Shekhar government in 1990-91.
On hearing the news of his death, SP Chief Mulayam Singh Yadav and other senior leaders left for Allahabad to attend Mishra's last rites, Chaudhary added.
A four-time Lok Sabha member, Mishra was a central minister in the governments headed by Morarji Desai, Chaudhary Charan Singh, V P Singh, Chandrashekhar, H D Deve Gowda and I K Gujral.
He held portfolios like Petroleum, Chemicals and Fertilisers, Energy, Shipping and Transport, Communication and Railways.
Mishra's last rites will be performed at Allahabad tomorrow afternoon, party sources said.