In this research, Taguchi Method is used for optimizing the quantity of the samples in investigating the properties of composite material. The objective of this study is investigating the validity of Taguchi method to optimize the sample quantity in the research on the impact strength of polymer matrix composite reinforced with oil palm fibers. The result was compared to the full factorial design. There were 3 Factors used in this work, i.e.: fiber contents/ percentage, Fiber length and chemical treatment. Every factor consists of three levels. The fiber contents were varied into 3 different percentages: 5%, 7% and 10%. The fiber lengths were also varied in three sizes: 5mm, 7mm and 10mm. The level of chemical used factors consist of Untreated, Treated and Coupling agent. NaOH is used here to treat the fiber while PPgMA (Polypropylene grafted Maleic Anhydride) is used here as The coupling agent. The analysis graph, from the two methods were obtained almost same graph. The analyze of multiple regression analysis also results similar regression equation, with the p-value of all independent variables also below 0.05 which indicated all independent variables are significant. Even There are little different in coefficient number of the two equation. But still too small. Taguchi method has succeeded in making research more efficient. The use of a small number of sample combinations is able to produce good analytical validity, equivalent to a full factorial method which is 3 times the number of combination samples.