Stalin, who flew in from Chennai this morning, met Kanimozhi at the Tihar jail accompanied by DMK Parliamentary Party Leader T R Baalu and MP A K S Vijayan.
The atmosphere was emotionally-charged, and Stalin and Kanimozhi were seen talking to each other for some time in Tamil. The meeting lasted for over 30 minutes.
Stalin had earlier met Kanimozhi at the Special CBI court here on May 24, four days after she was arrested in connection with the 2G scam.
The DMK leader also met former Telecom Minister A Raja and Sharad Kumar, Managing Director of Kalaignar TV, in the jail.
Prison officials allowed the meeting after a request in this regard was made by a DMK MP.
Stalin`s visit to Delhi comes a week after his father and DMK chief M Karunanidhi met Kanimozhi at the Tihar jail.
Karunanidhi, who met Kanimozhi at the jail last week, had told reporters on his return from Delhi that his daughter was shut in the prison in an "inhuman manner".
He had also stated that Kanimozhi was suffering from blisters and swelling on her body.