"He suffered a massive heart attack in the morning when he was working at the party office," a senior CPI leader said.
He was 72 and is survived by his wife, son and daughter-in-law.
Panda was a three-time CPI MP from Midnapore Lok Sabha constituency since 2001 till 2014.
Known for his organisational skills, Panda was elected as the state secretary of CPI in the last party conference.