This paper documented pre-service secondary teachers levels of proof writing in the Philippines. Construction of proof is an important skill for those who have interest in mathematics. However, literature revealed that proof construction is widely acknowledged to be one of the most challenging aspects in the mathematics curriculum. A sample of 28 pre-service secondary teachers participated in the study. Data were collected by means of written tests and focus group discussions. Most of them applied empirical approaches, where an assertion is valid from a small number of cases only, in their written proofs and left some items unanswered. The results of the study indicate that there is a necessity to conduct further investigations into the underlying reasons to strengthen the pre-service teachers ability to provide quality education to students, as pre-service teachers play a critical role in shaping the future of education and ensuring that every student has equal access to a high-quality education.