The Never-ending Apple Watch Patent Battle

The ongoing patent dispute between Apple and Masimo has become one of the most significant modern examples of how high-stakes patent rights shape product design, market access and innovation in consumer health-technology.

Some background

Masimo is a medical-monitoring technology company best known for its pulse-oximetry innovations used in clinical environments. Apple, meanwhile, has spent years expanding the health-tracking capabilities of the Apple Watch. That overlap has led to a multi-year court battle involving patent infringement, employee poaching allegations and even product import bans.

The dispute

Masimo alleges that Apple hired away key Masimo engineers and incorporated Masimo's patented blood-oxygen monitoring technology into the Apple Watch. Over the past six years, Masimo has asserted more than 25 patents across several U.S. courts and the International Trade Commission. On Friday 14 November 2025, a California federal jury ruled that Apple's workout mode and heart-rate notification features infringed Masimo's patent, awarding USD634 million in damages.

Masimo hailed the decision as a major win for protecting its inventions. Apple disagreed strongly, arguing that most of Masimo's asserted patents have been found invalid and that the remaining patent in this case is an expired, decades-old patient-monitoring patent. Apple will appeal.

This verdict is only one part of a much broader fight.

In 2023, the ITC blocked imports of certain Apple Watch models after finding infringement of Masimo's pulse-oximetry patents. Apple responded by removing blood-oxygen features entirely from U.S. models, later redesigning how the readings are performed by shifting part of the processing to the paired iPhone. Masimo is now challenging Customs' approval of that workaround, while Apple is separately asking an appeals court to overturn the ban.

Why this matters for patents

This case underscores the extraordinary strategic and commercial importance of core medical-sensor patents. Even a single expired patent - if infringed during its term - an trigger massive damages, force product redesigns and impact entire product lines.

It also illustrates how legal definitions become critical. A central question for jurors was whether the Apple Watch could legally be considered a “patient monitor,” a classification that would make Masimo's patent apply more directly. Arguments over accuracy, continuity of monitoring and Apple's own internal descriptions all played a role.

The conclusion

Masimo's latest victory ranks among the largest patent awards against a consumer-technology company. With appeals, ITC proceedings and Customs challenges still underway, the Apple - Masimo patent battle is far from over - and remains one of the most fascinating modern IP disputes to watch.

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