For the first time in 65 years, the Congress will be the No.2 party in Rajya Sabha.
The BJP has overtaken the Congress to become the largest political party in the Rajya Sabha, where it now has 58 members against 57 of the main opposition party.
BJP MP Sampatiya Uikey, who was elected to the Upper House following a bypoll in Madhya Pradesh took oath on Thursday. The election was necessitated after the death of Union minster, Anil Madhav Dave.
It's a huge news for the saffron party as it has become the number one formation for the first time in the RS after the Narendra Modi government came to power in May 2014.
The BJP-led NDA, however, is still short of a decisive majority in the House but the joining of JD(U) to the ruling block has further boosted its numbers.
There will be a big boost next year for the BJP when it wins eight of nine Uttar Pradesh seats that will be vacated, after sweeping assembly elections in the state this year.
Although there's been no announcement of alignment yet, BJP's new partnership with Nitish Kumar's Janata Dal United in Bihar is expected to help too. The JDU has 10 lawmakers in the Rajya Sabha.
Union Finance Minister Arun Jaitley said that this is a "natural consequence of our support base increasing". He said that the party's "base will increase in every election".
With inputs from PTI