Objective: To examine whether characteristics of children and adolescents who start lifestyle intervention (LI) for obesity in Germany changed over the last decade. Methods: 65,453 subjects (<21 years) from the APV database (Adiposity Patients Registry) with a BMI ≥ 90th percentile were included (years 2005-2015). Logistic regression models (confounders: age, sex, migration background) were created for overweight, obesity, extreme obesity, and obesity-related comorbidities. Comorbidities were further adjusted for weight category. Results were stratified by inpatient or outpatient care. Results: Extreme obesity was found to be more frequent at the onset of LI (2005: 11.6; 2015: 12.7%) with a similar trend in subgroups (p < 0.001). Obesity increased (2005: 50.3%; 2015: 55.1%), and overweight decreased (2005: 34.1%; 2015: 29.0%) in the whole study population. Trends were similar for inpatient or outpatient care (all p < 0.001). Hypertension increased from 45.7% to 49.2% in the whole study population, and similar data were obtained in the subgroup of inpatients (both p < 0.0001). Dyslipidemia increased in all patients (2005: 21.9%; 2015: 28.0%) and in inpatients (2005: 20.2%; 2015: 25.7%; both p < 0.0001). Abnormal carbohydrate metabolism rose in all patients (from 5.2 to 6.4%; p = 0.0002) without significant trends in subgroups. Conclusion: During the last decade, children and adolescents presented with higher BMI SDS at the onset of LI and the proportion with obesity-related comorbidities increased. Particularly the presence of comorbidities differed between outpatients and inpatients.