On January 25, 2019, the Commission on Elections (COMELEC) announced that the BOL was "deemed ratified" after results in the first part of the plebiscite showed majority support for the law's ratification.

During the February 6 referendum, however, 63 of the 67 Cotabato barangays, and 9 of 22 towns in Lanao del Norte saw voters in favor of joining the then-proposed region.

[2][4] On September 9, 2024, the Supreme Court of the Philippines upheld the validity of the Bangsamoro Organic Law, but declared unconstitutional the provision that considered the provinces of the former ARMM to be one unit for purposes of determining ratification.

[9] A total of 62 localities was initially announced to have made bids to participate in the plebiscite, although not all of them were contiguous to the defined Bangsamoro core territory.

[18] Fifteen satellites centers were set by the Comelec, one of which was in a camp controlled by the rebel group Moro Islamic Liberation Front (MILF), which played a major part in the conception of the BOL.

During the same period, the following acts were also prohibited: the establishment of a new voting precinct or alteration of the territory of an existing one, the transfer or detail of officers and civil service employees, the organization and maintenance of "strike forces" or similar entities, and the suspension of any elective public official from the barangay to the provincial level including elective officials in independent cities.

[26] Hataman also said that Christian practices such as fiestas and eating pork would not be made illegal should the BOL be ratified contrary to what people against the legislation is saying in their campaign.

[30] The provincial government of Lanao del Norte campaigned for a "No" vote since it opposed the inclusion of six of its municipalities in the proposed Bangsamoro Autonomous Region.

Lanao del Norte Governor Imelda Quibranza Dimaporo as well as her husband Abdullah and son Mohammad Khalid, who were both members of the House of Representatives lead the provincial government's campaign.

Abdullah Makapaar, the leader of the Moro Islamic Liberation Front's North Western Mindanao Command, campaigned for a "Yes" vote – promising to double the salary of teachers and the establishment of orphanage centers in the province.

[34] Voters in the existing ARMM had to answer one question:[20] In Filipino: "Payag ba kayo na pagtibayin ang Batas Republika Blg.

11054 na kilala din bilang "Organic Law for the Bangsamoro Autonomous Region in Muslim Mindanao"?In Arabic: ه‍ل أنت توُد الموافقة على القرار الجمه‍ورى رقم ١١٠٥٤ المعروف باسم: "القانون العضوى للحكم الذاتى امنطقة بانجسامورو فى مسلمى مينداناو".English translation: Are you willing to adopt the Republic Act No.

The question was presented as follows: In Filipino: "Payag ba kayo na isama ang Lungsod Isabela, Basilan sa Rehiyong Awtonomo ng Bangsamoro?

"In Arabic: هل انت توافق على ادراج مدينة ايسابيلا، باسيلان فى الحكم الداتى لمنطقة بانجسامورو؟English Translation: "Are you willing to include the city of Isabela, Basilan in the Bangsamoro Autonomous Region?

"Voters in the cities of Isabela and Cotabato were asked one question: whether or not they were in favor of their locality's inclusion in the proposed Bangsamoro Autonomous Region.

[37] The election body reasoned that the move was to allow the resolution of pending petitions for voluntary inclusion of additional local government units in the plebiscite.

A few restrictions and regulations were to be imposed such as the requirement for the observer to identify themselves to election authorities at the site and for them to provide copies of their report to the government.

In addition, it questioned the provision that the ARMM would be considered as "one geographical area" for the purpose of the plebiscite as well as the Moro Islamic Liberation Front's lead role in the Bangsamoro Transition Commission to the prejudice of other Muslims who are affiliated with other rebel groups and non-Muslims.

On January 25, the Commission on Elections, as the National Plebiscite Board of Canvassers, announced that a majority of voters in Cotabato City voted in favor of inclusion in the BARMM.

[46] A majority of voters in the six Lanao del Norte towns voted in favor of their municipality's inclusion in the Bangsamoro, and in the cases of Munai and Tangcal, overwhelmingly, to join the BARMM.

[52] The Dimaporos, holders of the top elective positions in the province, were against their towns joining the Bangsamoro (although supported the creation of it) and campaigned against the measure.

The military stated that it had received reports that the Abu Sayyaf, with foreign collaboration, had been planning to attack an urban area for a "long time" and insisted that it had yet to establish a connection between the bombings and the plebiscite itself.

[64][65] The United Nations and the European Union acknowledged the Bangsamoro Organic Law and the result of the plebiscite as a significant achievement in the Mindanao peace process.

[66] The government of Turkey issued a statement with the same message,[67] while Japan has pledged continued support for aiding developments in Mindanao in accordance with the peace process.

[66] Following unofficial results, that the majority of voters in Lanao del Norte voted against the inclusion of six municipalities of the province in the Bangsamoro Autonomous Region, the Philippine National Police decided to keep officers stationed in various parts of the province for election duties for the plebiscite to remain in anticipation of adverse reaction to the defeat of the "Yes" votes.

[68] The Commission on Elections announced on January 25, 2019 that the BOL was "deemed ratified", which meant that the ARMM would be abolished and that the process of the formal establishment of the Bangsamoro Autonomous Region would begin.

The election body also confirmed on February 14, 2019, that all six Lanao del Norte municipalities which could then-potentially be part of the new region voted in favor of their inclusion but failed to gain approval from voters in other towns in the province.

[69][70] The barangays that would be part of the BARMM did not immediately secede from their parent municipalities and province once the Bangsamoro Autonomous Region was effectively established.

However, it declared unconstitutional the provision in the law whereby the provinces of the former Autonomous Region in Muslim Mindanao would considered as one unit for the purpose of determining ratification by simple majority.

Thus, it ordered the exclusion of Sulu province, where 45.70% of the votes were cast in favor of ratification, from the Bangsamoro Autonomous Region in Muslim Mindanao.