OBJECTIVES: The aim of this study was to evaluate duration and  cost of prophylactic use of antibiotics, as well as occurrence of postoperative infection in the patients (pts) with laryngeal and pharyngolaryngeal carcinoma during 2005 and 2010. METHODS: Histories from 87 pts (2005) and 92 pts (2010) who were treated during the year 2005. and 2010. from laryngeal and pharyngolaryngeal carcinoma at the ENT Clinic, Clinical Center of Vojvodina, Novi Sad, Serbia, have been used. All pts received triple drug therapy perioperatively. Since 2009, additional hygienic measures and education of staff (in terms of the proper use of antibiotics) have been taken to improve hospital treatment. From the patients' histories, we followed: average length of hospital stay,average length of administrating antibiotics,occurrence of infection or other postoperative complication (fistula) and the price of used antibiotics. RESULTS: During 2005, antibiotics were administrated as follows: aminoglycosides (amikacin) 2x500mg during 10 days, cephalosporin (cefazolin amp. 2x1g, cefrtriakson 2x1g) 10 days, metronidazole (solutio) 3x500mg 10 days.During 2010, same anibiotics were administerd for an average of 3 days. The average length of hospital stay was in 2005. was 13.5 days, x+/- SD=13.5+/-4.2, and in 2010 was 11.18 days, x+/- SD=11.18+/-5.9.  The average length of administrating antibiotics was 9.4 days in 2005 (x+/- SD=9.4+/-1.1) and in 2010 was 3.4 days (x+/- SD=3.4+/-1.7). Occurrence of infection was in 4 pts (2005) and 6 pts (2010). The cost of used antibiotics in 2005.was 775748 dinars (9320 euros), and in 2010. was 366159 dinars (3698euro). CONCLUSIONS: With reducing the length of administrating same antibiotics, after additional hygienic and educative measures have been taken,  it is possible to significantly reduce the length of hospital stay (while the number of postoperative infections is not significantly increased) and  cost of used antibiotics, which altogether leads to reduction of overall cost of hospital treatment. :