Blood pressure measurement is an essential component of the general examination of every patient and the sphygmomanometer is one of the most commonly used diagnostic medical devices. The accuracy of sphygmomanometers depends strictly on performing the correct maintenance and calibration process of this equipment. The aim of this study was assessing the calibration condition of sphygmomanometers in use of primary care especially in physicians and general practitioner's office. The metrological reliability of more than two hundred manual sphygmomanometers in use in over 150 physician's offices and small clinics was evaluated. Quantitative analysis showed the amount of the obtained results in some equipment is critical and over the standard limitations. Primary care practitioners should have a system to ensure that their sphygmomanometers are recalibrated regularly according to the national or international standards. Using a mal-calibrated medical device has serious ethical, social and health implication to the society in general and to the misdiagnosed or mistreatment patient in particular. So, the obtained results show there is serious need for new and severe regulations on periodic performance verifications and medical equipment quality control program.