Ujiarpur Assembly constituency is an assembly constituency in Samastipur district in the Indian state of Bihar. The constituency was formed following the Delimitation Order of 2008.
As per Delimitation of Parliamentary and Assembly constituencies Order, 2008, No. 134 Ujiarpur Assembly constituency is composed of the following: Ujiarpur community development block; Sultanpur Ghataho, Chakbahauddin, Mokhtiyarpur Salkhani, Panr, Pachpaika, Harishankarpur, Kewanta, Nagargama, Pagra, Nawada, Basariya Plgram panchayats and Dalsinghsarai notified area of Dalsinghsarai CD Block.
Ujiarpur Assembly constituency is part of No. 22 Ujiarpur (Lok Sabha constituency).
In the 2015 state assembly elections, Alok Kumar Mehta of RJD won the newly constituted Ujiarpur seat.