Glutaric aciduria type I (GA-I) is an inborn error of lysine and tryptophan metabolism. Clinical manifestations of GA-I include dystonic or dyskinetic cerebral palsy, but when the symptoms occur, treatment is not effective. In Taiwan, newborn screening for GA-I started in 2001; we wish to evaluate the outcomes of patients detected through newborn screening. Newborns diagnosed with GA-I by abnormal dried blood spot glutarylcarnitine (C5DC) levels followed in our hospital were included in this study. They were treated with special diets, carnitine supplements, and immediate stress avoidance. Six patients were included in this study. All patients were treated prior to reaching 1 month of age. They were followed up with for 4 to 9 years. One patient had encephalopathic crisis episodes prior to turning 1 year old that caused pallidal lesions. Another patient had a chronic progressive disease during infancy that caused bilateral putamen lesions. These two patients had delayed development, but their brain lesions were resolved. The other four patients ran uneventful courses. They had normal intelligenece, ranged between average to low average level and their brain magnetic resonance imaging showed only high intensity over deep white matter. Patients with GA-I diagnosed by newborn screening have promising outcomes, though the risks of disease progression prior to 1 year of age remain significant.