Background: Assessing self-advocacy and transition readiness is an integral part of any transition plan for adolescents with chronic conditions to ensure a successful transition to adult healthcare and positive health outcomes. In adolescents with chronic and end-stage kidney diseases, this assessment is of exceptional importance because of the complexity of the treatment and care process. Purpose: To assess self-advocacy skills and care transition readiness among adolescents with chronic and end-stage kidney diseases. Design: A descriptive study was conducted on 105 adolescents with chronic and end-stage kidney diseases at the hemodialysis unit and nephrology outpatient clinic in the pediatric university hospital (Zagazig University Hospitals). Instruments; An interview questionnaire, the patient self-advocacy scale, and the transition readiness assessment questionnaire. Results: It was found that more than two-thirds of the studied adolescents with chronic and end-stage kidney diseases had low total self-advocacy skills and nearly three-fifths of them had low readiness for transition from pediatric to adult health care. A highly statistically significant positive correlation was found between total self-advocacy skills and total transition readiness of the studied adolescents. Conclusions: Adolescents with chronic and end-stage kidney diseases had low self-advocacy skills and low readiness for transition from pediatric to adult healthcare. Moreover, self-advocacy skills and transition readiness were positively correlated. Recommendations: Comprehensive transition programs with structured transition planning, transition education, support, family involvement, and regular assessments to evaluate readiness and adjust the plan as needed should be implemented.