We report herein our interesting case series of 15 infants admitting with neurological symptoms who were found to have vitamin B12 deficiency. Infants who were admitted to our hospital between 2004 and 2007 with neurological symptoms and were found to have vitamin B12 deficiency were included in this study. Data regarding clinical and laboratory features were obtained. Of 15 infants, 9 were boys (60%) and 6 were girls (40%). The mean age was 11.7 months. Anorexia, pallor, hypotonia, and neurodevelopmental retardation were present in all infants. Seizures and tremor were observed in 46.6% (7/15) and 33% (5/15) of patients, respectively. Seizures were generalized tonic-clonic in 4 patients, generalized tonic in 1 patient and focal in 2 patients. Four patients had tremor on admission and 1 patient had occurrence after vitamin B12 treatment. Vitamin B12 deficiency may lead to serious neurological deficits in addition to megaloblastic anemia. Persistent neurological damage can be prevented with early diagnosis and treatment. We believe that a thorough clinical and neurological assessment might prevent failure to notice rare but possible vitamin B12 deficiency in infants with neurological deficits and neurodevelopmental retardation.