Proton magnetic resonance spectroscopic imaging (1H MRSI) has demonstrated decreased N-acetyl compounds (NA) in the epileptogenic hippocampus in patients with temporal lobe epilepsy. We studied 8 patients with frontal lobe epilepsy and found mean NA/creatine (Cr) in the epileptogenic frontal lobe decreased by 27% compared with that of the contralateral homologous region (1.81 +/- 0.36 vs 2.49 +/- 0.60, p < 0.008). In every patient, NA/Cr was decreased in the epileptogenic region by at least 5%. These findings suggest that 1H MRSI may be useful in the presurgical evaluation of patients with frontal lobe epilepsy.