The meal was cooked Monday in the school in Dharmasati Gandaman village in Saran district, a district official said.
"A total of 103 school children ate the mid-day meal Sep 16. After the July 16 tragedy, no meal was cooked in the school for two months as parents and villagers were against it," the official said.
Authorities persuaded the villagers to accede to the resumption of mid-day meals.
"As per an official order, teachers of the school first tasted the midday meal and then served it to children," the official said.
Rameshwar Mahto, a villager, said children brought lunch from home last month.
The primary school does not have its own building and was earlier running from a one-room community centre when the tragedy occurred.
Around 16 mn children in 72,000 schools across Bihar eat mid-day meal everyday.
Later, the state government shut the primary school and clubbed it with a middle school in the village, said Amarjeet Sinha, state principal secretary for education.
A special investigation team probing the incident is yet to submit its final report.
A forensic lab report confirmed traces of insecticide in the cooking oil used to cook the mid-day meal July 16. Nearly 50 children were admitted to hospital where 23 died.
Around 16 million children in 72,000 schools across Bihar eat the mid-day meal every day.