Under the Mexican Trademark Law there is no obligation to use a trademark until renewal time is reached in the 10th year as of the filing date of the registration to be renewed and when filing the application for renewal it is only necessary to declare under oath that the mark has been used during a term of the last three years.
Notwithstanding the above, Article 130 of the Industrial Property Law, provides that if a registered trademark is not used in Mexico for three consecutive years the corresponding registration will become contestable unless registrant or duly recorded licensee had used the trademark during the three consecutive years prior to the filing date of a cancellation action based on non-use against it or that non-use was caused by circumstances beyond the will of registrant that have constituted an obstacle for the use of the trademark, such as import restrictions or other governments requirements applicable to the goods or services covered by the trademark.
In other words, although a registration would be vulnerable due to lack of use, it will be in force until its renewal time.
Likewise, if the trademark is in use and a three year period expires, nothing should be done but we could file a communication informing IMPI that it has been used for a period of three consecutive years.
This communication is recommendable to discourage third parties from taking frivolous cancellation actions on account of non use but it is not mandatory nor in compliance with any particular provision of the law; it should be considered just as a precautionary measure but will not prevent a third party from taking cancellation action anyway.
In any event, if a trademark is not in use during three year periods in Mexico but clients are interested in obtaining protection, we recommend to re-file for the mark of interest.
Source Managing Intellectual Property Magazine, Dec 2011/Jan 2012