The bomb was found near S.K. Memorial hall, hardly 50 metres from Gandhi Maidan. The bomb was defused by the bomb disposal squad, police officials said.
The live bomb was found and defused hardly half an hour before the union home secretary was to visit Gandhi Maidan to take stock of the situation after the string of explosions left six dead and over 80 injured.
According to police officials, the bomb was found when a police team was on a drive to search for hidden bombs.
"Immediately the team of the bomb disposal squad defused it," a police official said.
Suspecting more live bombs were in and around Gandhi Maidan, Patna Senior Superintendent of Police Manu Maharaj appealed to people to tell them if they spot any suspicious article.
"Police have requested people not to touch any suspicious articles and inform police immediately if they find anything," Maharaj said.
Police, till now, have recovered four live bombs from Gandhi Maidan.
The string of blasts took place Sunday before Bharatiya Janata Party's prime ministerial candidate Narendra Modi was to address a rally.