The invention relates to multimeric forms of antimicrobial peptides, for example, defensin peptides. The multimeric forms of defensin peptides possesses antimicrobial activity and may be formulated into antimicrobial compositions, pharmaceutical compositions, eyedrop composition, contact lens solution compositions for coating medical devices and the like. The invention also relates to the use of these multimeric forms of peptides, e.g. multimeric forms of defensin peptides for inhibiting and/or reducing the growth of microorganisms in general, including in a host. The invention further relates to a method of preparing multimers of peptides derived from defensins, for example hBD3.