Background: By removing tissue that is obstructing the Osteo Metal Complex (OMC) and facilitating drainage, functional endoscopic sinus surgery (FESS) preserves the mucous membrane and normal non-obstructing anatomy. The present study was conducted to determine complications of functional endoscopic sinus surgery (FESS). Materials & Methods: 95 adult patients of chronic rhino sinusitis selected for functional endoscopic sinus surgery (FESS) of both gendersunderwent anterior and posterior rhinoscopy examinations. Nasal endoscopy findings are graded using the Lanza Kennedy criteria, which consider the presence of polyps, oedema, and secretion. The traditional Messerklinger procedure was used to operate on all of the patients while they were under general anesthesia. Following surgery, all patients were monitored on a regular basis for three to six months. Results: Age group 20-30 years had 22 males and 19 females, 30-40 years had 18 and 15 females and >40 years had 10 males and 11 females. The difference was non- significant (P>0.05). Common clinical findings were post nasal drip in 24, headache in 51, nasal obstruction in 75, nasal discharge in 14, halitosis in 12, anosmia & hyposmia in 7 and earache/ ear fullness in 5 patients. The difference was significant (P< 0.05). Common complications were synechia seen in 24, bleeding nose in 11, orbital subcutaneous emphysema in 6 and lower lid ecchymosis in 5 patients. The difference was significant (P< 0.05). Conclusion: Synechia, orbital subcutaneous emphysema, lower lid ecchymosis, and bleeding nose were typical side effects of functional endoscopic sinus surgery.