Failure of lower urinary tract drainage constitutes one of the most frequent urological emergencies, predominantly affecting males but also relevant in females under specific circumstances. This chapter comprehensively discusses the pathophysiology, epidemiology, diagnosis, and management strategies for common conditions causing impaired urinary drainage, including benign prostatic hyperplasia, malignant prostatic diseases, urethral strictures, urinary tract infections, urothelial malignancies, neurological abnormalities, and trauma. Emphasis is placed on effective clinical assessment, urgent management strategies, and identification of potential pitfalls in treatment approaches. Detailed management algorithms and diagnostic tools are also provided to aid clinicians in making rapid, accurate decisions in emergency settings, ultimately improving patient outcomes.