Measurement of the carotid intima-media thickness enables arterial wall thickening to be quantified during preclinical disease stages. However, little is known about how the thickness varies in individuals with no cardiovascular risk factors. The objective of this study was to report on the range of carotid intima-media thicknesses observed in a population of healthy subjects with no cardiovascular risk factors and to identify parameters that influence it. The carotid intima-media thickness was assessed in 138 subjects (64 men and 74 women) aged 20-79 years whose age and sex were homogeneously distributed. The upper limit of normal for the mean carotid intima-media thickness ranged from 0.59-0.95 mm in men and from 0.52-0.93 mm in women. The upper limit for the maximum thickness varied from 0.81-1.11 mm in men and from 0.66-1.13 mm in women. The main parameters determining the intima-media thickness were age, male sex, systolic blood pressure and low-density lipoprotein cholesterol level.