Shivraj Singh Chouhan-led BJP had won 19 out of the 28 seats in the bypolls held on November 3.
28 MLAs elected in the recent bypolls in Madhya Pradesh were administered the oath as members of the Assembly on Monday by protem speaker Rameshwar Sharma, a government official said.
They were supposed to take oath on the first day of the winter session of the Assembly which was scheduled to begin on Monday.
However, after the session was postponed due to some Assembly staffers and MLAs testing positive for coronavirus, the oath ceremony was held in the office of the speaker, he said.
Those who took oath were BJP legislators Pradyumn Singh Tomar, Mahendra Singh Sisodia, Brajendra Singh Yadav, Bisahulal Singh, Dr Prabhuram Choudhary, Rajwardhan Singh Dattigaon, Hardeep Singh Dang, OPS Bhadoria and Tulsiram Silawat.
Their party colleagues Raksha Santram Sironia, Govind Singh Rajput, Pradyumn Singh Lodhi, Sumitra Devi Kasdekar, Kamlesh Jatav, Suresh Dhakad Rathkheda, Jajpal Singh Jajji, Manoj Narayan Singh Choudhary, Narayan Patel and Subedar Singh Sikarwar also took oath.
The other nine MLAs who were administered the oath were from the Congress, namely Mevaram Jatav, Rakesh Mawai, Kunwar Ravindra Singh, Ajab Singh Kushwaha, Dr Satish Sikarwar, Suresh Raje, Vipin Bankhede, Pragilal Jatav and Ramchandra Dangi.
The ruling BJP had won 19 out of the 28 seats in the bypolls held on November 3, taking its strength in the 230 member House to 126.
The tally of the Congress, which won nine of the 28 bypoll seats, is 96.