OBJECTIVE The aim of this study was to evaluate whether poor oral hygiene is associated with the intima-media thickness of the carotid arteries, which is one of the predictors of future progression of subclinical atherosclerosis. METHODS We selected 108 patients during periodontal examinations according to their oral hygiene. The patients had no history of atherosclerotic disease. The results of carotid artery B-mode ultrasonography examinations were analyzed at baseline and after a mean of 7.8 months. Patients were scored on the DMFT index for the number of decayed (D), missing (M), and filled (F) teeth (T). We also used the Silness-Loe plaque index (SLI) to evaluate oral hygiene and dental plaque. The patients were divided into 2 groups according to DMFT and SLI criteria. Group I had a DMFT index of 0 to 3 and an SLI score of 0 or 1; group II had a DMFT index of 4 to 28 and an SLI score of 2 or 3. RESULTS Dental status and oral hygiene were significantly associated with carotid artery intima-media thickness. Patients with increasing DMFT and SLI indices were correlated with intima-media thickness of the carotid artery. CONCLUSIONS Chronic poor oral hygiene and tooth loss are related to subclinical atherosclerotic changes in the carotid arteries and might be indicative of future progression of atherosclerosis.