Occupational Mn exposure results in extrapyramidal system findings and cognitive impairment. We aimed to evaluate the effect of occupational exposure to Mn on cognition and quantitative EEG (qEEG) data in Mn exposed workers. One hundred seventy-five workers with occupational Mn exposure were included in this study. Pallidal index (PI) values were calculated in T1 weighted sequence of brain magnetic resonance imaging (MRI).The presence of T1 hyperintensity on MRI was evaluated by two independent neurologists. The serum, spot urine, and 24-hour urine samples were measuredMn levels. The total scores of MoCA test and sub-groups were determined. The qEEG measures were analyzed. Right/left PI values in manganese exposed group were statistically higher than in control group (p<0.001).A positive correlation was detected between serum Mn levels and PI values and MRI T1 hyperintensity. There was no correlation between PI values and MoCA total/subgroup scores or qEEG measures. MoCA total score, abstraction and memory scores were found to be low in workers with T1 hyperintensity. No association between PI values, MoCA total or subtotal scores and qEEG data was determined in Mn exposed workers. When T1 hyperintensity was detected by the clinician on MRI, abstraction and memory were found to be the first cognitive functions affected at that time. These parameters could be used by occupational physicians as a screening test to assess cognition in periodic examinations of welders.