The profiling of microRNAs (miRNAs) using microarray technology has been used in many recent biological and medical studies. In this study, arrays of peptide nucleic acids (PNAs) were prepared and their miRNA capture abilities were evaluated. We found that the sensitivity of 10-mer PNA probes in targeting miRNAs was much higher than that of the corresponding DNA probes and also of longer (20-mer) DNA probes.