<i>Background:</i> Lipoprotein(a) [Lp(a)] or metabolic syndrome (MS) is individually considered an atherosclerotic factor. Serum Lp(a) may reportedly show the additive effects on atherosclerosis under certain particular pathologies. We do not know the association between serum Lp(a) and carotid artery intima-media thickness (CIMT) with relation to MS in older people. <i>Objective:</i> The present study aims at investigating the relationship between Lp(a) and CIMT levels in relation to MS among older subjects. <i>Methods:</i> We studied 182 Japanese subjects of ≧60 years (mean 72.5 years), free of cardiovascular/cerebrovascular disease. MS was based on the NCEP-ATPIII criteria with a minor modification for Japanese. The CIMT was ultrasonographically measured. <i>Results:</i> The CIMT levels were significantly greater in the MS group (n = 60, 1.03 ± 0.22 mm) than the non-MS group (n = 122, 0.96 ± 0.22 mm). Multivariate analysis, using Lp(a) levels or the product term for interaction between Lp(a) and MS, showed that age significantly and independently correlated to CIMT, along with male gender. <i>Discussion:</i> Even when Lp(a) and MS were simultaneously considered, age was the best determinant of CIMT in this population. The mechanism of our results including weak additive effects of Lp(a) and MS among older subjects may be partly throughout aging.