Development of array technologies started in the late 1980s and was first extensively applied to DNA arrays especially in the genomic field. Today this technique has become a powerful tool for high-throughput approaches in biology and chemistry. Progresses were mainly driven by the human genome project and were associated with the development of several new technologies, which led to the onset of additional "omic" topics like proteomics, glycomics, antibodyomics or lipidomics. The main characteristics of the array technology are (i) spatially addressable immobilization of a huge number of different capture molecules; (ii) probing the array in a simultaneous and highly parallel manner with a biological sample; (iii) tendency towards miniaturization of the arrays; and (iv) software-supported read-out and data analysis. We review some general concepts about peptide arrays on planar supports and point out technical aspects concerning the generation of peptide microarrays. Finally, we discuss recent applications by describing relevant literature.