Yadav was earlier posted as DG, Criminal Investigation Department (CBCID), and took charge from AK Jain, who retired as DGP today.
Jain had retired on March 31 but was given three months extension by the state government.
The new DGP is considered close to the Samajwadi Party leaders, sources said.
He was made ADG, Law and order, after Akhilesh Yadav took charge as Chief Minister in 2012.
"I am grateful to the government to give me the responsibility. I will ensure that law and order of the state is maintained.