Short answer. Article 280 of the Labor Code looks at whether you were engaged to perform activities usually necessary or desirable in the employer's usual business or trade. If so, you are regular regardless of what any written or oral agreement says — unless the job is genuinely fixed-term project work or seasonal in nature.
What the law says
an employment shall be deemed to be regular where the employee has been engaged to perform activities which are usually necessary or desirable in the usual business or trade of the employer
Labor Code, Article 280 — Regular And Casual Employment. Read the full provision →
What the law says
The provisions of written agreement to the contrary notwithstanding and regardless of the oral agreement of the parties
Labor Code, Article 280 — Regular And Casual Employment. Read the full provision →
The test looks at the work, not the contract
Article 280 measures regular status by what you actually do, connected to what the business actually is. If the tasks you perform are usually necessary or desirable to the employer's usual business or trade, the law deems the employment regular. Critically, this is stated to apply regardless of the oral agreement of the parties and notwithstanding any written agreement saying otherwise — a contract labeled "casual" or "contractual" does not change the analysis if the underlying work fits the description.
What 'usual business or trade' means here
The comparison is between the specific activity you perform and the employer's ordinary line of business. Work that is routine to what the company does day to day — not a one-off, unrelated, or incidental task — tends to fall inside the article's description. The statute does not supply a checklist beyond that phrase, so the question in practice is whether your role is a recurring part of how the business normally operates, rather than something outside its ordinary course.
The two situations the article carves out
Article 280 expressly excludes two kinds of engagement from the regular-employment description: work fixed for a specific project or undertaking, where completion or termination was determined at the time you were engaged, and work that is seasonal in nature, employed only for the season's duration. If your role genuinely fits one of those categories, this article's test for necessary-or-desirable work does not automatically make you regular — the exception applies on its own terms.
The one-year proviso, and what it does not decide alone
Separately, the article adds that anyone who has rendered at least one year of service, continuous or broken, is considered regular with respect to the activity they were employed in, for as long as that activity continues. That proviso does not replace the necessary-or-desirable test — it is an additional route to regular status based on tenure. Whether your particular work qualifies under either route depends on facts specific to your job and your employer's actual business, which is worth walking through with a lawyer if your status is being disputed.