Chowdhury wrote, "I am writing to express my regret for having mistakenly used an incorrect word to describe the position you hold."
"I assure you that it was a slip of the tongue. I apologize and request you to accept the same," he added.
Previously, Chowdhury had said that the BJP was "making a mountain out of a molehill." He also added, "I have sought time from the President and will apologise to her, but not to these 'pakhandis'."
The National Commission for Women (NCW) sent a notice to the Congress leader and asked him to appear before it in person and tender a written explanation for his remarks. The hearing is set to take place on 3 August.
An FIR was also filed in Madhya Pradesh's Dindori against him for the remarks.
Subsequently, the Bharatiya Janata Party on Thursday had mounted a fierce attack on the Congress and demanded an apology for Chowdhury's remarks.
Sonia-Smriti Face-Off Over Comments
Union Minister Smriti Irani said in the Upper House, "The Congress is not able to digest that a tribal daughter of a poor home has become president. Sonia Gandhi, you sanctioned the humiliation of Droupadi Murmu."
Launching an attack on Congress supremo Sonia Gandhi, Irani demanded that Gandhi apologise for Adhir Ranjan Chowdhury's contentious remark.
Nirmala Sitharaman claimed that Chowdhury's remark was "a deliberate sexist insult. Sonia Gandhi should apologise to the president of India and the country."
After the ruckus, Sitharaman alleged that Sonia Gandhi came up to BJP MPs to find out what was happening, which threatened the members. She added that when one of the BJP members approached Gandhi, she said "You don't talk to me."
The BJP has claimed that Gandhi walked up to MP Rama Devi in the Lower House, asking what her fault was. Irani intervened in the situation, which is when the Congress president allegedly spoke with hostility.
The Congress, however, has contended this saying that all Gandhi did was approach Rama Devi in a "dignified manner," and that she was then heckled and gheraoed by the BJP.
Meanwhile, Congress General Secretary in-charge of Communications, Jairam Ramesh, condemned the comments made by Smriti Irani in the Parliament.
"Atrocious and outrageous behaviour by Union Minister Smriti Irani in the Lok Sabha today! But will she be pulled up by the Speaker? Are rules only meant for the Opposition?" he tweeted.