| Name of the Candidate | Party Name | Result |
| MANGITA DEVI | Rashtriya Janata Dal | 55699 |
| PANKAJ KUMAR MISHRA | Rashtriya Lok Samta Party | 41589 |
| GUDDI DEVI | Samajwadi Party | 16038 |
| LAL BABU ROY | Independent | 5024 |
| VIJAY KUMAR SAH | Independent | 2821 |
| DEVENDAR PRASAD YADAV | Communist Party of India (Marxist) | 1887 |
| SHYAM BABU YADAV | Bahujan Samaj Party | 1520 |
| MRIGENDRA KUMAR | Shivsena | 999 |
| RAM NARESH BHAGAT | Independent | 941 |
| ARJUN PRASAD | Independent | 924 |
| KIRAN PASWAN | Rashtravadi Janata Party | 820 |
| CHAUDHARY KHUSHWANT SINGH | National Janta Party (Indian) | 790 |
| RAJARAM PASWAN | Bahujan Mukti Party | 598 |
| BAJRANG BIHARI SINGH | Independent | 565 |
| None of the Above | None of the Above | 7249 |
| AC No | Category | Poll Phases | Last Date of Nominations | Date of Polls | Result |
| 29 | GEN | Phase IV | Oct 7th 2015 | nov 1st 2015 | Nov 8th 2015 |
Runnisaidpur is part of the Sitamarhi Lok Sabha constituency. Runnisaidpur CD block, Kauria Raipur, Gaura, Bath Asli, Mohini and Pandaul Buzurg gram panchayats of Nanpur community development block areas came under the Runnisaidpur assembly segment. Runnisaidpur is in Sitamarhi district of the state. A total of 2,39,801 are eligable voters among these, 1,27,711 are male while 1,12,085 are female.
One of the assembly constituencies located in the Sitamarhi district of Bihar, Runni Saidpur was retained by Guddi Devi of the Janata Dal (United) in the last assembly polls to Bihar in 2010. In that election, She had secured 36125 votes to trounce her nearest Rashtriya Janata Dal (RJD) rival Ram Shatrughan Rai by a margin 10759 votes. Ram Shatrughan Rai, who received 25366 votes, was followed by independent candidate Mangeeta Devi who polled 14125 votes.
Moni Gupta of the Congress came fourth with 10114 votes. Former Runni Saidpur MLA Nawal Kishore Shahi, who entered the fray on the ticket Sharad Pawar led Nationalist Congress Party (NCP), was relegated to the seventh place by securing just 3703 votes.
The BJP did not field its candidate for Runni Saidpur seat because it was contesting the 2010 assembly elections in alliance with the JD (U). However, as things stand today, the BJP and the JD (U) have parted ways and the Lok Janashakti Party (LJP), the ally of the RJD in the last assembly elections, is now a part of the BJP led NDA, the ruling dispensation at the Centre. In a bid to survive, the RJD, the JD (U) and the Congress have come together to check the BJP.
Guddi Devi had won the previous assembly elections in October/November in 2005 by defeating the then sitting RJD MLA Bhola Rai who had won the seat in 1995, 2000 and February 2005. While Bhola Rai won the 1995 elections on the ticket of the Janata Dal, his wins in 2000 and 2005 came as a nominee of the RJD.
Earlier Nawal Kishore Shahi had been elected from the Runni Saidpur assembly constituency in 1977, 1985 and 1990.
One of the six assembly segments located in the Samastipur district of Bihar, Runni Saidpur is one of the six assembly constituencies that combine to form the parliamentary constituency of Sitamarhi which is currently represented by Ram Kumar Sharma of the Rashtriya Lok Samata Party (RLSP) who won the seat by defeating his nearest rival Sitaram Yadav of the RJD by a margin of 147965 votes in the 2014 Lok Sabha elections which resulted in the formation of Narendra Modi government at the centre. The RLSP, which entered into an alliance with the BJP, contested three parliamentary seats in Bihar in 2014 and won all of them riding on the Modi wave that was sweeping the country at that time.
Other five assembly constituencies in the Sitamarhi Lok Sabha seat are Bathnaha, Parihar, Sursand, Sitamarhi and Bajpatti.
Mangita Devi (RJD) is locked in a battle with Pankaj Mishra of Rashtriya Lok Samata Party (RLSP) in Runnisaidpur of Sitamarhi district. Guddi Devi, the two-term JD(U) legislator from Runnisaidpur, claimed that she was assured by Chief Minister Nitish Kumar that she would get the party ticket from this constituency. Nitish, it is said, even asked Guddi to begin work in Runnisaidpur as she would be contesting again from there. But she was denied the ticket at the last minute.
Runnisaidpur segment is presently represented by Guddi Devi of JD (U) in the state assembly. She defeated RJD's Ram Shatrughan Rai by a margin of 10,759 votes in the assembly elections held in 2010. Guddi Devi got 36,125 votes while Ram Shatrughan Rai managed 25,366 votes only.Now Guddi Chaudhary Devi is contesting on a Samajwadi Party ticket as the Third Front candidate afer she quit JD(U) over the denial of ticket by Nitish Kumar.