The main cytokines which participate in the etiopathogenesis of aneurysms of the abdominal aorta (AAA) are: tumour necrotizing factor (TNF), interleukins 1b, 2, 6 and 8 (IL 1b, 2, 6, 8), platelet growth factor (PDGF) and endothelin 1, 2 (ET 1, 2). The objective of the presented work was to assess whether plasma levels of these cytokines can be used as endogenous markers of the size and symptomatology of AAA and also to what extent they correlated with hypertension which is a serious risk factor of AAA. During the three-year period (1995-1997) 86 patients with AAA were examined. The control group (n = 30) was formed by patients admitted for planned cholecystectomy. Plasma levels of all investigated cytokines with the exception of IL 8 in AAA differed markedly from the levels in the control group (p < 0.05-p < 0.0001). Changes in levels of IL8 and ET 1, 2 were significant in relation to the size of AAA (p < 0.05 and p < 0.01 resp.). The IL8 levels together with TNF in hypertonic patients correlated with the size of the AAA (p < 0.05 and p < 0.01 resp.), in normotonic subjects with the levels of IL 1b and IL2 (p < 0.05). The TNF levels were significant in symptomatic AAA (p < 0.05). The rising or declining levels of some plasma cytokines can serve as plasma markers of the growth and symptomatology of AAA.