Ornithine transcarbamylase deficiency (OTCD) is an X-linked disorder of metabolism of the urea cycle. It usually causes hyperammonemic encephalopathy in males during the neonatal to-infantile period, whereas female carriers present with variable manifestations depending on their pattern of random chromosome X inactivation in the liver. Early clinical manifestations of hyperammonemiaare nonspecific often leading to a delay in the diagnosis of OTCD.Unfortunately, delays in initiating treatment often lead to poor neurologic outcomes and overall survival. Presentation of hyperammonemic encephalopathy in children with OTCD is rare, and the mortality and morbidity rates are high. The diagnosis of OTCD and aggressive management of hyperammonemia were of paramount importance for appropriate treatment and successful recovery. Here, we report theclinical, biochemical, and molecular findings in a child with OTCD who presented with acute hyperammonemic encephalopathy.