Sangeeta, a student of class IV, and Neelu, who studied in class I, ate the mid-day meal in the school and fell sick when they reached home last evening, they said.
They were admitted to a primary healthcare centre at Harsinghpur where Sangeeta died last night, while Neelu succumbed this morning.
Their families alleged that the deaths occurred because of the "poisonous food" they ate at the school. Sitamarhi District Magistrate V N Jha said the cause of death would be ascertained only after autopsy.