Introduction: Ketamine is a cornerstone of paediatric procedural sedation because of its haemodynamic stability , preservation of airway reflexes, and favourable safety profile. Serious hypersensitivity reactions due to ketamine are exceptionally rare, and ketamine-induced anaphylaxis is scarcely documented in infants. Here, we report a rare, life-threatening episode of anaphylaxis following ketamine administration for lumbar puncture. Case presentation: A previously healthy 9-month-old infant admitted with febrile convulsions and persistent fever underwent lumbar puncture to exclude meningitis. Intravenous ketamine (0.5 mg/kg) was administered for sedation. Within minutes, the child developed cough progressing rapidly to stridor, tachycardia, and weak pulses with cold clammy extremities, indicating anaphylactic shock. Immediate resuscitation was initiated according to paediatric anaphylaxis algorhythms, including repeated intramuscular adrenaline, aggressive fluid resuscitation, antihistamines, nebulized adrenaline and intravenous adrenaline infusion. Despite initial treatment, persistent respiratory distress with a characteristic staccato breathing pattern prompted urgent multidisciplinary review . However, additional corticosteroid therapy resulted in a gradual clinical improvement without the need for airway intervention. The infant made a complete recovery with no residual complications or neurological sequelae. Conclusions: This case underscores that ketamine, despite its established safety , can rarely precipitate severe life-threatening anaphylaxis. Vigilant monitoring during sedation, readiness for rapid resuscitation, and awareness of atypical presentations are essential to prevent catastrophic outcomes. Informed consent for procedural sedation should include discussion of rare but life-threatening adverse reactions. Reporting such cases is crucial to enhance clinician awareness and improve patient safety during paediatric procedures requiring sedation.