This comes as a major improvement for the saffron party from the 17 seats it won in the 2014 General Elections.
The victory would gain significance, as in the last state Assembly elections held just a year back, there was neck and neck fight between the BJP and the Congress, which, after a lot of political drama, led to a Congress-Janata Dal-Secular coalition government in the state.
The Congress is so far leading in two seats and JD-S in one, the EC data showed.
In Bangalore South, 28-year-old Tejaswi Surya, BJP's youngest candidate led the race by 3.22 lakh votes, against Congress's B.K. Hariprasad. Surya was selected as the BJP candidate after the death of six-time MP and former Union Minister Ananth Kumar last year.
The candidature of Surya came as a surprise to many as there were expectations that Kumar's wife Tejaswini Ananth Kumar would be given the party's ticket from the constituency.
D.V. Sadananda Gowda, the incumbent MP from the Bangalore North constituency, seems well in place to retain the seat as he leads the race by 1.4 lakh votes ahead of Krishna Byregowda, the current Rural Development and Law Minister in the Karnataka government.
The BJP leads in three out of the four constituencies in Bengaluru, with the party's P. C. Mohan leading against Congress' Rizwan Arshad. Congress' D.K. Suresh is leading in Bangalore Rural.
In a massive blow to the Congress, its heavyweight and current MP, M.Veerappa Moily is trailing by 1.81 lakh votes to BJP's B.N.Bache Gowda in Chikkballapur constituency. In the 2014, he won the seat by 9,520 votes.
( With inputs from IANS )