Background: Although substantial numbers of stroke patients suffer from apathy, its causes are still poorly understood. Previous studies suggest that dysfunction of the frontal lobes is implicated in the pathophysiology of motivation. Our aim was to investigate the association between proton magnetic resonance spectr oscopy (H1-MRS) measurements in unaffected frontal lobes and apathy in a group of first-time stroke patients. Methods: 31 patients with a first-time ischemic stroke located outside the frontal lobes and 20 healthy subjects were included in the study. The authors performed single voxel H1-MRS in order to measure the N-acetylaspartate/creatine (NAA)/Cr, glutamate +glutamine (Glx)/Cr, choline ( Cho)/Cr and myo-inositol (mI)/Cr ratios in the frontal lobes. Patients were ass essed between days 7 and 12 post stroke. Diagnosis of apathy was made on the bas is of clinical observation, interview and Apathy Scale. Results: 13 out of 31 patients (42%) demonstrated apathy. Patie nts with apathy had lower NAA/Cr ratios in the right frontal lobe than non-apat hetic subjects. The patient group was divided into two subgroups: Those with lef t hemisphere strokes, and those with right hemisphere strokes. Of these subjects , significantly lowered NAA/Cr ratios were found in the right hemispheres of apa thetic patients in the subgroup with left-sided brain lesions. Conclusions: The se findings point to the association between apathy and frontal lobe integrity, suggest different reactions of the hemispheres and indicate that changes in the NAA/Cr ratio are related to the apathy. Background: Although substantial numbers of stroke patients suffer from apathy, its causes are still poorly understood. Previous studies suggest that dysfunction of the frontal lobes is implicated in the pathophysiology of motivation. Our aim was to investigate the association between proton magnetic resonance spectroscopy ( H1-MRS) measurements in unaffected frontal lobes and apathy in a group of first-time stroke patients. Methods: 31 patients with a first-time ischemic stroke located outside the frontal lobes and 20 healthy subjects were included in the study. The authors performed single voxel H1-MRS in order to measure the N-acetylaspartate / creatine (NAA) / Cr, glutamate + glutamine (Glx) / Cr, choline (Cho) / Cr and myo-inositol (mI) / Cr ratios in the frontal lobes . Patients were ass essed between days 7 and 12 post stroke. Diagnosis of apathy was made on the bas is of clinical observation, interview and Apathy Scale. Results: 13 out of 31 patients (42%) reflected apathy. Patie nts w ith apathy had lower NAA / Cr ratios in the right frontal lobe than non-apat hetic subjects. Those patient groups was divided into two subgroups: Those with lef t hemisphere strokes, and those with the right hemisphere strokes. Of these subjects, NA NAA / Cr ratios were found in the right hemispheres of apa thetic patients in the subgroup with left-sided brain lesions. Conclusions: The se findings point to the association between apathy and frontal lobe integrity, suggest different reactions of the hemispheres and indicate that changes in the NAA / Cr ratio are related to the apathy.