The ongoing patent dispute between Masimo and Apple regarding the Apple Watch blood oxygen monitoring feature has entered a new phase. Masimo, a medical technology company, has filed a lawsuit against the US Customs and Border Protection (CBP) following the agency’s decision to permit the feature’s restoration.
The dispute began when Apple launched the blood oxygen monitoring capability with the Apple Watch Series 6 in 2020. This functionality employs pulse oximetry technology, which measures blood oxygen saturation levels by directing light through the user’s skin. Masimo alleged that Apple infringed upon its patents by incorporating proprietary technology, reportedly obtained through the hiring of former Masimo employees.
In 2023, the US International Trade Commission (ITC) ruled in favor of Masimo, determining that Apple had violated two of its patents. Consequently, the ITC issued an import ban on Apple Watch Series 9 and Ultra 2 models that included the active blood oxygen feature. To comply, Apple disabled the feature via software, enabling continued sales but limiting device capabilities.
On August 1, 2025, CBP approved Apple’s redesigned implementation, which shifts blood oxygen calculations from the Watch to the paired iPhone. This adjustment allowed Apple to announce on August 14 that the feature would be reinstated for US customers through a forthcoming software update.
Masimo’s lawsuit contends that CBP exceeded its authority, violated due process rights under the Fifth Amendment, and contravened the Administrative Procedure Act. Masimo argues that the decision was made through an ex parte process without transparency or opportunity for input, effectively undermining the ITC’s exclusion order by permitting infringing functionality when the devices are used together.
The complaint seeks a temporary restraining order to vacate CBP’s approval and revert to its January 2024 decision, which required complete deactivation of the feature for imported devices. Masimo asserts that the ongoing approval irreparably harms its market position.
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