L-2-hydroxyglutaric aciduria was diagnosed in a 9-month-old female infant after a complex febrile convulsion with subsequent transient left-sided hemiplegia. The symptoms were consistent with acute hemiconvulsion-hemiplegia-epilepsy syndrome. Magnetic resonance imaging (MRI) of the brain revealed distinct white-matter abnormalities in the bifrontal and bioccipital periventricular area and increased signal intensity in the lenticular, caudate, and dentate nuclei, consistent with L-2-hydroxyglutaric aciduria. Increased concentrations of L-2-hydroxyglutaric acid were detected in the urine, plasma, and cerebrospinal fluid. The patient was homozyous for the p.Lys81Glu (c.241A>G) missense mutation in the L-2-HGA gene, confirming the diagnosis of L-2-hydroxyglutaric aciduria. Acute hemiconvulsion-hemiplegia-epilepsy syndrome has not been reported as a presenting feature in L-2-hydroxyglutaric aciduria. In patients with prolonged or complicated febrile seizures such as hemiconvulsion-hemiplegia-epilepsy syndrome, L-2-hydroxyglutaric aciduria should be included in the differential diagnosis, especially in children with concomitant macrocephaly.