Holding placards, banners and Panchsheel flags, the protesters gathered at the Reserve Bank square (Samvidhan Chowk) in the city and condemned the blasts.
They shouted slogans and stopped vehicular traffic, which was then diverted from the square.
Some Buddhists monks were also part of the demonstration, police and eye witnesses said.
Nine low-intensity serial blasts rocked the Maha Bodhi Temple complex and adjacent areas today, leaving two monks injured.