This paper presents a method of flexible pavement design and performance using a mechanistic-empirical pavement design guide (ME-PDG) as a tool for pavement design in the Philippines. The study was made using three types of traffic condition for both flexible pavements of the treated and untreated subbase. The initial design was performed using the local design guide which is based from the AASHTO 1993 design guide. The results were then evaluated using ME-PDG for its performance. The designs are then adjusted to meet with the results given by ME-PDG. All the simulation and computations in this study were performed using a program, based on the guide, created in MATLAB software. Results showed that top-down cracking failure is the most critical and greatly affects the smoothness of the pavement. It was also observed that the use of treated sub base is very effective in distributing the loads applied to the pavement and helps decrease the damage experienced by the pavement. The study concluded that ME-PDG yields more realistic and less conservative results compared to the AASHTO 1993 design guide. However, further studies should be performed to gather enough data to produce accurate and correct results.