Infection of the nephro-urological system remains a common and clinically challenging problem, particularly in patients with atypical presentations, prior instrumentation, or underlying immunosuppression. Conventional anatomical imaging plays a central role in identifying obstruction, collections, and complications but is often limited in distinguishing active infection from sterile inflammation or post-interventional change. Nuclear medicine techniques provide complementary functional and molecular information that can clarify disease activity, define extent, and influence patient management. This review presents a practical, nuclear medicine–focused overview of imaging approaches for nephro-urological infection. Established techniques, including ⁹⁹ᵐTc-DMSA imaging, radiolabelled white blood cell scintigraphy, and 18F-FDG PET/CT, are discussed with emphasis on tracer biology, physiological renal handling, and common interpretive pitfalls. Clinical scenarios such as acute and chronic pyelonephritis, renal abscess, transplant infection, and device-related infection are used to illustrate appropriate tracer selection and integration with anatomical imaging. Special populations, including paediatric patients, immunocompromised individuals, and renal transplant recipients, are considered, alongside practical algorithms and teaching points aimed at improving clinical applicability. Emerging developments in bacteria-specific tracers, quantitative imaging, and hybrid modalities are also reviewed. By adopting a biologically informed and question-driven approach, nuclear medicine can play an increasingly important role in the diagnosis and management of nephro-urological infection.