Flank pain is a common presentation in general practice. The most frequent causes are renal calculi, followed by acute pyelonephritis. Due to shared neural pathways, flank pain may also originate from adjacent abdominal, musculoskeletal, gynaecological, or vascular structures. In rare cases, psychological or factitious causes may be involved. This chapter offers a concise guide to identifying likely diagnoses by evaluating the patient's risk factors alongside predictive symptoms and signs. Recommended investigations are outlined to help support or exclude specific conditions. Once a diagnosis is established, evidence-based management and monitoring strategies are provided in line with current clinical guidelines. Preventive measures are also discussed to reduce the risk of recurrence. A final summary table highlights the key features of emergency conditions that warrant urgent referral or hospital admission.