The Aam Aadmi Party leader was granted bail after furnishing a personal bond of Rs.50,000. The case will be heard on February 20.
Sanjay Singh told the media outside the court that he stood by his comments on Majithia.
"I will say this a thousand times that Majithia is involved in drugs smuggling in Punjab. I appeared before the court on my own as I respect the judicial system," he said.
Sanjay Singh, a close associate of Delhi Chief Minister Arvind Kejriwal, dared Majithia to file a police case against him (Singh) instead of filing the defamation case.
The AAP is challenging the ruling Shiromani Akali Dal-BJP alliance and the Congress in the February 2017 assembly polls.
Majithia is a cabinet minister in Punjab and the brother-in-law of Deputy Chief Minister and Akali Dal president Sukhbir Singh Badal. Majithia is the younger brother of union food processing minister Harsimrat Badal.