Hypersensitivity reactions during anesthesia are rarer in childhood when compared with adults. In both children and adults, neuromuscular blocking agents are the most frequently incriminated drugs in this setting followed by antibiotics. Benzodiazepines and ketamine are generally regarded as exceptional drugs regarding allergy. In this report, we present a 4-year old child who developed urticarial lesions during anesthesia and was found to have hypersensitivity to both midazolam and ketamine when diagnostic tests were performed.