| Name of the Candidate | Party Name | Result |
| HARI NARAYAN SINGH | Janata Dal (United) | 71933 |
| ARUN KUMAR | Lok Jan Shakti Party | 57638 |
| DHARMENDRA KUMAR | Independent | 4146 |
| BRIJ NANDAN YADAV | Jan Adhikar Party (Loktantrik) | 3128 |
| NEELAM KUMARI SINGH | Nationalist Congress Party | 2858 |
| SANTOSH KUMAR | Independent | 2093 |
| SITARAM PASWAN | Bahujan Samaj Party | 1959 |
| PINTU KUMAR | Independent | 1692 |
| CHANDRA UDAY KUMAR | Independent | 1450 |
| AMIT ANAND | Independent | 1262 |
| RAMDAS AKELA | Communist Party of India (Marxist-Leninist) (Liberation) | 1165 |
| MUNNA KUMAR | Aam Janata Party | 720 |
| ARJUN PRASAD | Independent | 586 |
| BIJAY KUMAR | Pragatisheel Magahi Samaj | 542 |
| None of the Above | None of the Above | 5523 |
| AC No | Category | Poll Phases | Last Date of Nominations | Date of Polls | Result |
| 177 | GEN | Phase III | Oct 1st 2015 | Oct 28th 2015 | Nov 8th 2015 |
Harnaut is a legislative assembly constituency in the Nalanda district of Bihar. Harnaut is a part of the Nalanda Lok Sabha constituency of the state. The Harnaut assembly segment has 2,74,937 eligible voters, out of whom 1,46,144 are males and 1,28,781 are females. Harnaut assembly constituency covers Nagar Nausa, Chandi and Harnaut community development blocks.
One of the seven assembly constituencies located in the Nalanda district of Bihar, Harnaut is currently held by Harinarayan Singh of the Janata Dal (United) who had retained it for the party in the last assembly polls to Bihar in 2010 by defeating his nearest Rashtriya Janata Dal (RJD) rival Arun Kumar by a margin of 15042 votes in a straight fight. While Harinarayan Singh, winner of the erstwhile Chandi assembly seat in 2005, received 56827 votes, the RJD candidate received 41785 votes.
Basundhara Kumari, who was nominated by the Congress to contest the Harnaut assembly seat in 2010, was relegated to the fifth place with just 1821 votes.
Once represented by the current Bihar Chief Minister Nitish Kumar, Harnaut is one of the seven assembly constituencies located in the Nalanda district, home district of Nitish Kumar. Hilsa, Rajgir, Islampur, Asthawan, Biharsharif and Nalanda are the other assembly seats located in the district. While Rajgir is currently represented by the BJP, the rest are held by the JD (U) MLAs.
Harnaut assembly seat went in favour of Sunil Kumar of the JD (U) in both the assembly elections in 2005. He was denied ticket by the JD (U) in 2010.
In 2000, Harnaut was claimed by Vishvamohan Choudhary of the Samata Party, the earlier avatar of the JD (U). SAP’s nominee Arun Kumar Singh had emerged victorious from the Harnaut assembly in a byepoll in 1996 which was necessitated by the vacation of the seat by Nitish Kumar who was elected in the previous assembly polls in 1995.
Nitish Kumar was earlier elected from the Harnaut assembly constituency in 1985 as a nominee of the Lok Dal. However his attempts to enter the Bihar Assembly in 1977 and 1980 on the tickets of Janata Party and Janata Party (Secular) came to naught.
Harnaut is one of the seven assembly constituencies that combine to form the parliamentary constituency of Nalanda which is currently represented by Kaushalendra Kumar of the JD (U) who retained the seat in the 2014 Lok Sabha elections.
Other six assembly constituencies that are parts of the Nalanda parliamentary seat are Biharsharif, Asthawan, Rajgir, Islampur, Hilsa and Nalanda.
LJP has fielded Arun Bind from Harnaut constituency to take revenge of his 2010 defeat by the sitting JD(U) MLA Hari Narayan. Hundreds of JD(U) workers and sympathisers from different panchayats under Harnaut constituency in Nalanda district expressed anger over the renomination of the sitting MLA to contest election. They registered their strong resentment over the renomination of incumbent JD(U) MLA Hari Narayan Singh at a mahapanchayat. The partymen threatened to vote against him if the CM did not replace the sitting MLA as the candidate in Harnaut constituency.