Array expression profiling of miRNAs has become a widely used technique and thereby gained a broader user spectrum from novice to highly experienced array specialists. In this chapter we discuss the challenges in designing microarrays for miRNA detection and show the advantages of LNA ™-enhanced capture probes. We cover important aspects of array normalization and show its practical application in a case study with miRNA data from the NCI-60 cell line panel. We also demonstrate that commonly used methods for normalization of mRNA expression arrays can be applied for miRNA array data. These methods are implemented in both open source and commercial software.