Carbohydrate microarrays, comprising hundreds to thousands of different glycan structures on solid surfaces in a spatially discrete pattern, are sensitive and versatile tools for the analysis of glycosylation changes in complex biological samples. Glycoarrays are also suitable for monitoring multiple molecular interactions with biomolecules where sugars are involved, offering a large variety of bioassay options. In this paper we review the most important glycan microarray types currently used with their main applications, and discuss some of the future challenges the technology faces.