The DMK MP reached the Lok Sabha post noon after question hour was over.
As cameras clicked away, Raja, who walked out of prison Tuesday evening after 15 months, did not respond to questions from the media.
A Raja (File photo)
Giving him bail, the court had said that he could not visit his former office, the department of telecommunications, or his home state Tamil Nadu without permission.
Raja resigned as minister Nov 14, 2010 after the Comptroller and Auditor General reported that his 2008 decision to allocate 2G spectrum on a first-come-first-served basis had caused the exchequer a presumptive loss of Rs 1.76 lakh crore.
The CBI arrested him Feb 2, 2011.