Cheap, rapid and user friendly tools for detection of microorganisms were intensively discussed during last decades. The use of immunospecific biosensors seems advantageous for samples originating from clinical, environmental and agricultural area, food processing and military. The piezoelectric (quartz crystal microbalance, QCM) and optical (surface plasmon resonance, SPR) biosensors represented by QCM Analyzer and Biacore 3000 were compared for future development of real-time and label-free microbial biosensors. The spores of Bacillus atrophaeus were used as a non-pathogenic surrogate for B. anthracis. Seven commercially available antibodies were immobilised on the sensor surfaces to select the most promising one. Various immobilisation techniques were used. The total time of analysis did not exceed 30 min and the estimated limits of detection (LOD) were 10^6 CFU mL-1 and 10^5 CFU mL-1 in case of QCM and SPR, respectively.