The goal of this study is to treat pineapple leaves fiber (PALF) with chitosan for antimicrobial properties. The treated PALF with chitosan was then crosslinked with crosslinking agent; butanetetracarboxylic acid (BTCA) to preserve chitosan in the PALF structure. The effectiveness of chitosan and crosslinking agent towards PALF was determined using untreated PALF, PALF treated chitosan, PALF treated chitosan (wash), PALF treated chitosan/BTCA and PALF treated chitosan/BTCA (wash). After the treatment with chitosan and BTCA, the treated PALF undergone the washing process to determine the effectiveness of BTCA to avoid the removal of chitosan from PALF during washing. The presence of chitosan in the PALF was confirmed using Fourier Transform Infra-red (FTIR) analysis. The treated PALF was then characterised in terms of its antimicrobial activity and mechanical properties. Antimicrobial activity test confirmed the presence of chitosan successfully retarded the growth of microbe. Tensile test analysis revealed the untreated PALF has the highest tensile strength compared to all treated PALF. In contrast, young modulus of the treated PALF shows increment relative to the untreated PALF. This study is particularly important for the further application of PALF or other natural fibers especially in medical and textile industry
