Prophylactic antimicrobial therapy is defined as the administration of an antimicrobial agent prior to contamination of previously sterile tissues or fluids, in an attempt to reduce the microbial burden of intraoperative contamination. Prophylactic antimicrobial therapy should cover the anticipated floral contamination, with therapeutic levels from incision to closure. There is level I evidence to support the use of prophylaxis in clean-contaminated head and neck procedures and tonsillectomy, while level II evidence fails to support the use of prophylaxis in clean head and neck procedures. The aim of this study was to evaluate the use, timing and appropriateness of antimicrobial prophylaxis perioperatively, in otorhinolaryngological/head and neck procedures. A total of 34/51 (66%) patients were administered antimicrobial agents prophylactically. Six of 19 patients (42%) who ought to have received prophylaxis did not, while six of 13 (46%) of those who did not require it received it. Administration was unsuitably timed in 14 of 34 (41%) operations. This study demonstrates unnecessary administration of antimicrobial agents perioperatively, subclinical intraoperative antimicrobial levels for prophylaxis and inconsistent documentation regarding prophylaxis in otorhinolaryngological/head and neck procedures in a general ENT unit.