The advantages of Internet of Things (IoT) technology have led to the development of Real-Time Tracking Systems (RTLS) used to identifying, monitoring and tracking objects within indoor or confined environments (e.g. devices, things or people tracking in factories, warehouses or offices, and even patients, biological materials, pharmaceuticals tracking in medical centers). One of technologies which may be incorporated in RTLS is RadioFrequency IDentification (RFID) system. Health care workers and patients displacement often requires approaching to RFID readers and thus exposure to the electromagnetic field emitted there. The aim of this ongoing study was to evaluate the specific energy absorption rate (SAR) values in the body of person present near ultra-high frequency (UHF) RFID readers operating at frequency range 865 - 868 MHz, considering various exposure scenarios (various number of single antennas fixed to the walls and their different location against human body: readers’ plane or their side located in front of or on the side of human body). The modelled electromagnetic field (EMF) source was rectangular microstrip antenna designed at resonance frequency in free space of 865 MHz. The SAR values were calculated in anatomically based numerical model of adult male. Preliminary results of this ongoing study showed that the SAR values may reach significant levels in some exposure scenarios. The SAR values in the body exposed to EMF 5 cm away from UHF RFID readers need consideration with respect to general public exposure limits, when radiated power exceed 3 W.