"I have written to Chief Minister Nitish Kumar mentioning inability to contest the Lok Sabha election from JD(U) because of shortage of time for preparation," Singh told PTI here.
"I thanked him for providing me opportunity to serve in the Rajya Sabha and said that preparation for Lok Sabha needs at least six months... Since there is a little time left for the polls it will not be possible for me to contest," he said.
Singh, a former Planning Commission member, has worked hard to build a new brand name for Bihar.
He has been credited with organising investment conclaves by inviting leading industrialists and foreign dignitaries to the state.