DNA arrays are revolutionizing the analysis of gene expression and single nucleotide polymorphisms of genomic DNA. Currently, the expression of 10–15|X% of human genes can be analysed simultaneously in a single experiment using cDNA or oligonucleotide-based format of DNA array. Alternatively, smaller DNA arrays with a limited number of selected genes, such as cytokines, growth factors or transcription factors, can be used. In concordance with Human Genome Project, after a few years, the DNA arrays will allow the analysis of expression of the whole human genome and will have a great impact on basic research, drug development and diagnostics. It is important to characterise mechanisms of atherosclerosis-related diseases at the level of gene expression so that new therapeutic strategies can be identified. With the aid of DNA array it is possible to identify multiple, simultaneous, transcriptional events that ameliorate or contribute to atherogenesis. The results are non-physical maps of the function, hierarchy and interactions of genetic programs. In this review we focus on DNA array technology and its applications in atherosclerosis research.