In this work an application of quartz tuning forks (QTF) in Pseudomonas aeruginosa biofilm growth monitoring is presented. QTF-based mass measurement method was examined regarding its applicability in P. aeruginosa biofilm mass evaluation during antibiotic treatment. Two antibiotics (gentamicin and ciprofloxacin) were tested on their antibacterial activity. Three independent methods were also applied for the experiments as a control for the performed QTF measurements: standard colony count of living cells, crystal violet colorimetric method for biofilm monitoring and microscopy visualization. Using quartz tuning forks the inhibition of Pseudomonas aeruginosa biofilm formation during antibiotic treatment was observed in correlation with other standard tests. These several experiments proved suitability and potential application of the presented technique in biofilm growth measurement for antibacterial compound activity evaluation.