The agency has written to the Income Tax department, alleging that Mr Yadav's wife, Sadhna, and his younger son Prateek, bought property that far exceeded their declared income.
The properties that the CBI has shortlisted for scrutiny were acquired between 1998 and 2003. They include a bungalow on MG Road in the cantonment area of Lucknow, two plots in Kamta Village of Lucknow that were bought for 18 lakhs but later sold for 2.5 crores by Prateek Yadav and a plot worth 18 lakhs in the Gomti Nagar area of the city.
The CBI says that because Prateek Yadav and his wife are not elected representatives, it cannot investigate them.
Last month, the CBI said that it has not found evidence that Mr Yadav misused his term as chief minister of Uttar Pradesh, to amass wealth and assets worth 2.63 crores for his family, as alleged by a lawsuit filed six years ago in the Supreme Court. (Read: CBI closes corruption case against the Yadavs)
The opposition has alleged match-fixing by the Congress, because Mr Yadav and his Samajwadi Party prop up the Prime Minister's minority government.