Parmalat immediately said it would appeal the decision.
Citigroup said that the Milan court had rejected in its entirety the demand for damages and interest totalling 1.8 billion euros filed by Parmalat in 2015 against it and several former employees.
The US bank said the Milan court viewed the claim it received as being identical to one Parmalat had filed in the United States which it lost at trial in 2008 and in appeal in 2011.
Citigroup said it was happy the claim was thrown out at an early stage, saying it avoided considerable legal fees to defend itself against allegations that were examined and rejected by US courts.
Parmalat collapsed in 2003 when 14 billion euros went missing from its accounts in what ranks as one of Europe's biggest financial scandals as it wiped out the savings of 135,000 people in Italy.
Investigations showed the group had been in trouble for many years, surviving only as a result of falsifications of its balance sheets and sophisticated financial instruments.
Parmalat founder Calisto Tanzi received a 17-year jail term for his role in the dairy group's collapse.
Parmalat shares dropped 1.2 percent in afternoon trading in Milan, which was up 1.4 percent overall.