Oracle has branded the lawsuit "malicious and meritless".
HP insists that Oracle is deliberately ignoring previous agreements in a bid to gain a competitive advantage.
"HP believes that Oracle's March 22 statement to discontinue all future software development on the Itanium platform violates binding commitments Oracle has made to HP and the more-than 140,000 shared HP-Oracle customers," said HP in a statement.
"Further, we believe that this is an unlawful attempt to force customers from HP Itanium platforms to Oracle's own platforms."
HP filed a civil lawsuit requesting that Oracle reverse its decision to the Superior Court of the State of California yesterday.
"We remain committed to a long-term mission-critical server roadmap, including Intel's Itanium processor," said HP.
Oracle claims it was asked by HP to guarantee continued support for Itanium in September 2010, while HP "already knew about Intel's plans to discontinue Itanium".
"HP issued numerous public statements in an attempt to mislead and deceive their customers and shareholders into believing that these plans to end-of-life Itanium do not exist. But they do," said Oracle in a statement.
Interestingly, Intel responded immediately to Oracle's outburst by issuing a statement that dismisses any claims of plans for ending Itanium development.
"Intel's work on Intel Itanium processors and platforms continues unabated with multiple generations of chips currently in development and on schedule," said Paul Otellini, president and CEO of Intel.
"We remain firmly committed to delivering a competitive, multi-generational roadmap for HP and other operating system customers that run the Itanium architecture".