When facing a patent litigation threat, potential defendants have the option to seek a declaration that they are not infringing. Until recently, however, that strategy carried a hidden risk: the burden of proof on the infringement issue could shift to the accused infringer, instead of resting with the patentee. The Supreme Court has now mitigated that risk by holding that the patentee must carry the infringement burden, regardless of who brings the action.
In Medtronic, Inc. v. Mirowski Family Ventures, LLC, the Court held that "when a licensee seeks a declaratory judgment against a patentee to establish that there is no infringement, the burden of proving infringement remains with the patentee." Mirowski accused its sub-licensee Medtronic of infringing patents relating to implantable heart stimulators, and Medtronic responded with a declaratory judgment action. After the trial court found Mirowski had failed to show infringement, Mirowski appealed, arguing that the burden was on Medtronic to show non-infringement since Medtronic brought the action. The Federal Circuit agreed, holding that, as a licensee and declaratory judgment plaintiff, the burden was Medtronic’s. The Supreme Court has now reversed, however, and confirmed that the burden remains on the patentee regardless of the form of the action.
Prior to Medtronic, it was not clear which party faced the burden on the infringement issue when a licensee brought a declaratory judgment action. That lack of clarity helped patentees by making declaratory judgment actions riskier. Medtronic now levels the field somewhat by making it clear that the patentee must do the heavy lifting to show infringement, regardless of who commences litigation. Some are concerned that licensees now have too much power to force the patentee into litigation. The Court reminded us, however, that the declaratory judgment action only arises when the patentee threatens litigation in the first place.
©2026 Carlton Fields, P.A. Carlton Fields practices law in California through Carlton Fields, LLP. Carlton Fields publications should not be construed as legal advice on any specific facts or circumstances. The contents are intended for general information and educational purposes only, and should not be relied on as if it were advice about a particular fact situation. The distribution of this publication is not intended to create, and receipt of it does not constitute, an attorney-client relationship with Carlton Fields. This publication may not be quoted or referred to in any other publication or proceeding without the prior written consent of the firm, to be given or withheld at our discretion. To request reprint permission for any of our publications, please use our Contact Us form via the link below. The views set forth herein are the personal views of the author and do not necessarily reflect those of the firm. This site may contain hypertext links to information created and maintained by other entities. Carlton Fields does not control or guarantee the accuracy or completeness of this outside information, nor is the inclusion of a link to be intended as an endorsement of those outside sites.
Related People
Of Counsel
