Vascular endothelium, monocytes and T-lymphocytes belong to the key cellular populations, which take an active part in the host's defence reactions. A successful course of these reactions is determined by a meticulous control of all phases since the very first steps until final healing of all incurred wounds. Any failure of the control mechanisms may lead to the development of chronic inflammatory diseases with an autoimmune component, such as the rheumatoid arthritis or atherosclerosis. An inflammatory reaction which is already under way is regulated by anti-inflammatory cytokines. However, of equal importance is the maintenance of cellular participants of inflammatory reactions in a quiescent state while no pro-inflammatory stimuli are present. One of the most important endogenous mediators, which prevent a self-initiated activation of endothelial cells, monocytes and T-lymphocytes, is represented by the transcription factor Krüppel-like factor 2. Its impact on the mentioned cells is almost identical with the so-called pleiotropic effects of inhibitors of the enzyme HMG CoA reductase or statins. This review article offers an insight into basic preventive mechanisms exerted by KLF2, notably those related to atherosclerosis.