The announcement was made by Mr Swamy and BJP president Rajnath Singh after they met at the Rajnath Singh's residence in Delhi.
"Time for a more nationalistic focus," said Mr Swamy.
Rajnath Singh told: "Swamy has been a part of Jan Sangh. Swamy has decided to merge Janta Party with the BJP. We welcome Swamy on joining BJP fold". Ref TOI