Samastipur is rich in agriculture, because of its fertile plain. Tobacco, maize, rice and wheat are the main crops. Leechi and mango fruits are grown in abundance. There is a jute mill in Samsastipur at Muktapur Village. This is very famous jute mill (Rameshwar Jute Mill), employing around 5000 people. Shekhopur is one of the best agricultural villages and it also has famous temple, Bhagwatisthan at Manipur. Samastipur has many a sugar mills which make it a prominent player in state’s sugar production.
Samastipur is major producer of potatoes. There are more than 20 cold storages in the district, all storing potatoes and total capacity is 650000 quintles.
Samastipur has also in race of consuming fertilizers.