Owing to molecular mimicry, periodontal pathogen carriage may result in a systemic cross-reactive immune response with the host. The analyses were performed to investigate if serum antibody levels to human heat shock protein 60 (HSP60) are associated with the antibody levels and salivary carriage of two periodontal pathogens, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, as well as with the dental status in patients with acute coronary syndrome (ACS). ACS patients (n = 141) were monitored at baseline when entering to hospital, and after 1 week, 3 months and 1 year. Periodontal status was recorded by dental radiographs, and A. actinomycetemcomitans and P. gingivalis were detected by PCR from saliva at baseline. Serum IgG and IgA antibody levels were determined at all time points. All antibody levels remained quite stable during the follow-up. Serum IgG-class antibody levels to A. actinomycetemcomitans and HSP60 had a strong positive correlation with each other at all time points (r∼0.4, P < 0.05). Mean serum IgG antibody levels to HSP60 were significantly higher in the A. actinomycetemcomitans IgG- and IgA-seropositive than in the seronegative patients, but did not differ between the pathogen carriers compared to the non-carriers. HSP60 antibody levels did not differ significantly between the edentulous, non-periodontitis and periodontitis patients. Despite the observed cross-reactivity in the systemic IgG-class antibody response to HSP60 and A. actinomycetemcomitans, the pathogen carriage in saliva or the periodontal status did not affect the HSP60 antibody levels in ACS patients.