We evaluated the possible association of the serum levels of C-reactive protein (CRP), serum amyloid A (SAA), fibrinogen, and cardiac troponin I (cTnI) with the presence of complex angiographic characteristics throughout the coronary artery tree in 519 consecutive patients with non-ST-elevation acute myocardial infarction (NSTEMI). Blood samples were obtained in the first 12h of NSTEMI invasion and all patients underwent in-hospital coronary angiography. Coronary lesions were classified as complex lesion (CL) or non-CL according to Ambrose criteria. Serum levels of CRP (p<0.001), SAA (p<0.001), or fibrinogen (p=0.001), but not of cTnI (p=0.9), were significantly related to the presence of multiple (> or =2) CLs. On the contrary, serum levels of cTnI (p<0.001), but not of CRP (p=0.5), SAA (p=0.9), or fibrinogen (p=0.9), were significantly associated with the severity of coronary artery disease. The results of the present study suggest that elevated levels of inflammatory biomarkers are associated with a generalized activation of coronary artery tree while elevated cTnI levels are associated with the severity of coronary artery disease in the setting of NSTEMI. It seems that inflammatory biomarkers and cTnI reflect different aspect of the process involved in unstable coronary artery disease.