The L-glutamate (Glu) and L-Acetyl-aspartate (NAA) are products N-acetyl-aspartyl-glutamate (NAAG) in a twin reaction which require the participation of neurons, oligodendrocytes and atrocities. Altered NAAG metabolism has been described, in some neurological conditions but not in autism spectrum disorders (ASD). Our previous studies using proton-Magnetic Resonance Spectroscopy (1H-MRS) in bilateral anterior (ACC) and posterior cingulate cortex (PCC) have described the altered neurometabolic patterns in adults with ASD. Aim. To compare NAAG, NAA, and Glu concentrations in the ACC and PCC in adults with ASD and typically developed (control) individuals. Methods. Single-voxel (1H-MRS) in bilateral ACC and PCC, in 19 adults with a clinical diagnosis of ASD and 41 controls, matched for age, gender. Autism quotients (AQ) score were assessed. One-way ANOVA and Bonferroni correction were applied. Results. The ASD group had a significant increase in glutamate [12.10 ± 3.92 (mM)] *p = 0.02; as well as a significant decrease in N-acetylaspartylglutamate [9.78 ± 0.49 (mM)] *p=0.02; compared with controls. Conclusions. Altered N-acetylaspartylglutamate and glutamate levels were found by MRS in individuals with ASD, suggesting new therapeutic avenues.