Labelling of food products that contain new technologies has been adopted to inform consumers and address concerns over uncertainty of the technologies. Even though food labelling is significant, the implementation of mandatory labelling measures for nanofood within the domestic legislation is only possible if the measure is aligned with the World Trade Organisation (WTO) regulations. This paper examines whether mandatory labelling measure for nanofood would be permissible under the WTO agreements, i.e. the Technical Barriers to Trade Agreement and the Sanitary and Phytosanitary Agreement. The study adopts a doctrinal approach and content analysis by examining relevant legal provisions in the WTO agreements, cases decided by the WTO, and other documents on nanofood labelling. Findings suggest that the labelling measure amounts to unnecessary barriers to international trade. The mandatory labelling is not an international labelling standard and the practice is trade restrictive. Some recommendations presented at the end of this paper shall give invaluable insights into the implementation of mandatory labelling for nanofood if any country decides to introduce the measures in their food information system.