The rules are enacted pursuant to paragraph 2, Article 28 of the Customs Law.

The term "least-developed countries" means those least-developed countries whose imports are applicable to preferential tariff rates listed in the second column of the Customs Import Tariff.

The rules for determining origins of import goods include:
(1) non-preferential rules of origin.
(2) rules of origin for least-developed countries.
(3) rules of origin for preferential trade agreements.

The origin of imported goods shall be ruled by the Customs Authorities at the place of importation. In the event of any doubt in the definition of origin of imported goods, the Customs Authorities at the place of importation shall request the obligated tax payer to provide a certificate of origin or samples within a given deadline.
The certificate of origin mentioned in the preceding paragraph shall include transaction documents, information related to the raw materials used on production of the imported goods, processing data, or other related information.
In the case that the obligated tax payer fails to provide a certificate of origin or samples within the given deadline as set forth in paragraph 1, or the certificate documents or samples provided by the obligated tax payer are insufficient to identify the origin of the imported goods, the Customs Authorities at the place of importation shall request other agencies to assist in the origin identification. Where the other agencies are not able to put forth specific opinions in writing within 20 days after the assistance request from the Customs Authorities at the place of importation, the Customs Authorities at the place of importation is entitled to determine the origin of the imported goods based on the collected data.
The other agencies as referred in the preceding paragraph include the Council of Agriculture of the Executive Yuan, the Ministry of Economic Affairs, and other related agencies.

In the process of defining the origin of the imported goods, the obligated tax payer requesting assistance from the competent authorities or professional organizations in defining the origin of the imported goods according to Paragraph 1 of Article 28 of the Customs Law shall notify the Customs Authorities at the place of importation. Upon receipt of the notification from the obliged tax payer, the Customs Authorities at the place of importation shall send the samples and data to the related agencies or professional organizations for assistance in defining the origin of the imported goods.
Upon receipt of the responses to the assistance request from the competence authorities or professional organizations, the Customs Authorities at the place of importation shall summarize the facts and evidences and determine the origin of the imported goods.

The Customs Authorities at the place of importation shall finalize the determination of the origin of the imported goods within two months after the import declaration date.
The determination period set forth in the preceding paragraph may be extended for two months in the event that further investigation is required. However, the extension is limited to one time only, and, in this case, the obliged tax payer shall be informed of the reason for such extension.