The objective of this work is to investigate the occurrence of atherosclerosis and metabolic syndrome (MetS) in ankylosing spondylitis (AS) patients (pts). Twenty-four consecutive AS pts (men, 87.5%; median age, 50.5 years; median disease duration, 16.5 years), fulfilling the modified 1984 New York criteria for AS criteria, and 19 age- and sex-matched controls were investigated. Clinical atherosclerosis was evaluated by physical examination for cardiovascular (CV) diseases and history or drug use for CV events. Subclinical atherosclerosis was detected by mean intima media thickness (a-IMT) and maximum IMT (max-IMT) of carotid arteries using ultrasonography. Laboratory investigations including fasting plasma glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides were assessed by standard methods, while homocysteine was assessed by chemiluminescence. MetS was assessed using the updated NCEP-ATP III criteria. Disease activity was defined according to the International Ankylosing Spondylitis Assessment Study criteria. The 10-year CV risk (%) profile was evaluated in agreement to the Progetto Cuore criteria. No major CV event was detected in the study population. No significant differences were found when AS pts and controls were compared according to the mean a-IMT (0.52+/-0.26 vs 0.51+/-0.13 mm), max-IMT (0.92+/-0.20 vs 0.85+/-0.39 mm), prevalence of abnormal max-IMT >1 mm (27.2 vs 5.3%), and 10-year CV risk (9.9+/-9.6 vs 3.6+/-1.8%). Systolic blood pressure (p=0.04), triglyceride to HDL cholesterol ratio (p=0.002), and LDL cholesterol (p=0.03) were found significantly higher in AS pts than in controls; on the contrary, HDL cholesterol was pointed out as significantly lower (p<0.001). MetS was found in 11/24 (45.8%) AS pts and in 2/19 (10.5%) controls (p=0.019). No significant relationship emerged in MetS prevalence among AS pts regarding the mean value of age, disease duration, Bath Ankylosing Spondylitis Functional Index, Bath Ankylosing Spondylitis Disease Activity Index, and the Italian version of Health Assessment Questionnaire. This preliminary report points out a higher prevalence of MetS in AS pts than in controls. Further studies are needed to confirm this finding.