Introduction: Mercury is considered by the World Health Organization as one of the top ten chemicals of major public health concern. Fish consumption is known to be the main source of exposure to mercury. It has been previously established that freshwater fish of the water bodies of the Vologda Region can be a significant source of mercury exposure in the local population. Objective: To establish the relationship between hair mercury concentrations in residents of the Vologda Region and diseases of the cardiovascular system. Materials and methods: The study involved 849 participants (274 men and 575 women) aged 18 to 94 years living in the city of Cherepovets (Vologda Region: 59° 07' N 37° 54' E). Occipital hair was sampled in accordance with WHO recommendations and then tested using the RA-915M mercury analyzer with a PYRO-915+ pyrolysis attachment (measurement range: 0.002–200 mg/kg) without preliminary sample preparation, by atomic absorption with Zeeman correction of non-selective absorption. The measurement accuracy was verified using the NIMD-01 certified reference material with the mercury concentration of 0.794 ± 0.050 µg/g. Results: The mean hair mercury concentration in the study subjects from the Vologda Region was 0.572 ± 0.686 mg/kg, which is 3.5 and 1.5 times lower than safe mercury levels of 2.2 and 1 mg/kg established by WHO and US EPA, respectively. Mean hair mercury levels in the study participants with/without cardiovascular diseases were 0.646 ± 0.727 mg/kg and 0.459 ± 0.589 mg/kg, respectively. The highest mercury levels were observed in male subjects with myocardial infarction (> 0.73 mg/kg) and in females with stroke and acute coronary syndrome (> 0.687 mg/kg). Conclusions: Mercury in the hair of people with diagnosed cardiovascular diseases (myocardial infarction, acute coronary syndrome, cerebrovascular accident, unstable angina, etc.) and without them has been found. The accumulation of mercury in the body can be one of the risk factors for the development of vascular and heart diseases.