The certificates of return were presented to them at the International Conference Centre, Abuja.
INEC said the certificates of return for the members-elect of the House of Representatives will be presented to them on Wednesday.
The commission had last week presented the certificates of return to the President-elect, Bola Tinubu, and the Vice President-Elect, Kashim Shettima.
So far, only seven of the 18 political parties in the country have at least a member in the Senate, said INEC Chairman, Mahmood Yakubu.
The parties are —the All Progressives Congress (APC), the Peoples Democratic Party (PDP), the All Progressives Grand Alliance (APGA), Social Democratic Party (SDP), Labour Party (LP), New Nigeria Peoples Party (NNPP) and the Young People Party (YPP).
As it stands, the ruling APC retains the majority members in the Senate with 57 seats while the PDP got 29 seats.