The aim of the study is to evaluate the incidence and risk factors of a second surgery of the adenoids or tonsils for hypertrophy in children who have already undergone surgery for the same condition. This is a retrospective study (2004–2013) based on data from the National patient registry in Sweden. A total of 41,401 children underwent a first surgery of the adenoids or tonsils during the studied period. The most commonly performed (first) surgical procedure was adenoidectomy followed by adenotonsillotomy, adenotonsillectomy, tonsillotomy, and tonsillectomy. A total of 4459 patients underwent a second surgery for the same condition. The incidence of a second surgery was the highest in the primary adenoidectomy group (72.2, 95% CI 69.7–74.7) and lowest in the primary adenotonsillectomy group (14.2, 95% CI 12.6–15.9). A lower age at first surgery significantly increased the risk for a second surgery. A second surgery of the adenoids and tonsils due to lymphoid hypertrophy was common in the pediatric population. Adenoidectomy stands out in a negative way in most aspects of this study compared to the other types of first surgery. However, due to the design of this study, the results of this study cannot be taken as proof of a full adenotonsillectomy as the most appropriate first surgery in children with lymphoid upper airway obstruction. Nevertheless, the results clearly show that the topic needs to be addressed in future studies.