IN THIS GUIDE · Write the employer letter so it settles the profession, the duties and the credential in one reading
Start with the TN eligibility and application overview
The letter has to name a listed profession and describe listed work
Biologist appears in Appendix 2 of the USMCA professionals chapter with a baccalaureate or licenciatura degree as the qualifying credential. The letter must therefore say that the position is that of a biologist, and the duties it describes must be the work of a biologist: designing surveys, analyzing population data, preparing habitat assessments. A title such as project coordinator is not disqualifying by itself, but the officer will compare the described duties with the profession claimed, and administrative or supervisory language that dominates the description undermines the claim. The letter should also state that the engagement is prearranged, temporary, for a defined period of up to three years, with a stated salary, and that the applicant will not be self-employed in the United States.
The credential attached must match the profession’s own rule
Each USMCA profession has its own qualification rule, and the officer applies the one attached to the profession named in the letter. For a biologist that is a bachelor’s degree in the field, so the degree certificate and transcript go with the letter. Field experience, published surveys and professional-society membership help explain the role but do not replace the degree, because the biologist entry has no experience-based alternative. If the degree is in a related discipline such as environmental science, the file should include course descriptions showing the biological content, since the officer decides whether the degree is in the profession rather than simply whether a degree exists.
Port of entry or petition, and what each option needs
As a Canadian citizen she can apply for TN admission directly at a U.S. port of entry or at a preclearance location with the letter, her degree and proof of citizenship, and no visa stamp is required. Alternatively the employer may file Form I-129 with USCIS and she enters after approval. The port-of-entry route is faster but the decision is made on the spot by an officer reading the documents; the petition route gives a written approval to present at the border and is sometimes preferred by employers who have never handled a TN. Either way the same three elements are tested: citizenship, a listed profession with its credential, and prearranged professional employment.
What usually goes wrong with a first-time employer
The most common failures are avoidable: a letter signed by a recruiter with no authority, an open-ended engagement with no stated end date, a job description copied from an internal posting that stresses supervision or client management, or an omission of the applicant’s citizenship and degree. A second failure is inconsistency between the letter and the résumé she hands over at the same time. The employer should be given a short checklist of what the letter must contain and asked to have it signed by an officer of the firm on letterhead. The applicant should bring the original degree, not a photocopy, and be ready to describe her actual daily work in the profession’s terms.
Sources reviewed 2026-09-07. This guide covers a preparation focus; it is not an individual eligibility assessment.