Self-measurement of blood pressure (BP) at home is more common than 10 years ago and encouraged by current guidelines to increase patient adherence to treatment and reach the goal of target BP. The aims of this study are to evaluate the accuracy of home sphygmomanometers and to investigate behavior/knowledge of the sphygmomanometer owners. A campaign was planned to determine the accuracy of home sphygmomanometers in 2006. Seven hundred and twenty-three home sphygmomanometers were brought by individuals to the University Hospital Hypertension Clinic within 1 year and 693 (96%) of the devices were in adequate working condition and suitable for analysis. Four hundred and thirty-nine (63%) of the sphygmomanometers were automatic. Four hundred and eleven (59.3%) of the 693 sphygmomanometer were inaccurate. About 80% (256/320) of the wrist devices were inaccurate. Most studies evaluating the accuracy of sphygmomanometers are conducted in hospital or primary care settings; studies investigating home sphygmomanometers are rare. High frequency of inaccurate home devices is a major public health problem. In conclusion, inaccurate devices have been used in home BP measurements frequently and frequency of device-related errors can be decreased by awareness and training of the patients. Physicians and healthcare providers should advise the patients to check the accuracy of their home sphygmomanometers regularly.