Introduction: Nephrotic syndrome is a rare but reported complication following various vaccinations, including the measlesmumps-rubella (MMR) vaccine. The pathophysiology involves immune-mediated glomerular damage, though the exact mechanism remains unclear. Temporal association between vaccination and onset of nephrotic syndrome has been documented in paediatric literature, warranting careful monitoring post immunization. Case presentation: A previously healthy 3-year-old girl presented with facial oedema, abdominal distension, and reduced urine output developing six days after receiving the MMR vaccine. Physical examination revealed periorbital oedema, ascites, and bilateral lower limb pitting oedema. Laboratory investigations showed proteinuria (4+ on dipstick),hypoalbuminemia (1.2 g/dL), and hypercholesterolemia (580 mg/dL). Serum creatinine was normal at 0.4 mg/dL. Renal ultrasound showed normalsized kidneys with increased echogenicity . The patient was diagnosed with Nephrotic syndrome based on clinical presentation and laboratory findings. Treatment was initiated with prednisolone 60 mg/km2/day . The child achieved complete remission after 3 weeks of corticosteroid therapy , with resolution of oedema and normalization of urinary protein levels. Conclusion: This case illustrates a temporal association between MMR vaccination and nephrotic syndrome onset in a paediatric patient. While causation cannot be definitively established, healthcare providers should maintain awareness of this potential adverse event. The favourable response to corticosteroid therapy suggests possible minimal change disease,consistent with vaccine-associated cases reported in literature. Continued surveillance and reporting of such cases are essential for vaccine safety monitoring.