Objectives: To examine potential benefits of perioperative antibiotic therapy in children undergoing adenotonsillotomy. Methods: Adenoidectomy with tonsillotomy was performed in 124 children with obstructive symptoms, aged 5–7 years. Of these, 120 completed the study. Intraoperative intravenous and postoperative oral clindamycin, or placebo for 7 days, were administered. Results: There were significant differences between the groups regarding pain intensity (p < 0.001) and duration (p < 0.05), day of return to normal physical activity (p < 0.05), occurrence and duration of oral malodor (p < 0.001), number of doses of additional analgesic (p < 0.001), healing grading (p < 0.05) and parents’/caregivers’ satisfaction scores on the 4th postoperative day. There were indications for antibiotic in 2 individuals in the placebo group. Conclusions: There are significant differences in the course of convalescence related to perioperative antibiotic in children after adenotonsillotomy, but strict indications for antibiotics in these patients are rare.