An elevated white blood cell (WBC) count is associated with nonalcoholic fatty liver disease (NAFLD); however, a leukocyte subtype that is involved in the pathogenesis of NAFLD is not known. This study was conducted to investigate the association between NAFLD and WBC subtype fractions (%) among healthy elderly Koreans. A total of 794 subjects who underwent a health check-up were investigated. After excluding excessive alcohol intake and other liver diseases, NAFLD was diagnosed based on sonographic findings: hyperechogenecity of liver tissue, difference of echogenicity between liver and kidney, and visibility of vascular structures. The prevalence of NAFLD among entire cohort was 39.0% (310/794). The presence of NAFLD was significantly associated with higher blood WBC counts (5,485 ± 1073 vs. 5,230 ± 995 per mm(3), p = 0.001) and monocyte fraction (6.08 ± 2.40% vs. 5.12 ± 1.31%, p < 0.001). The multiple logistic regression analysis, after controlling confounders, including age, gender, body mass index, systolic and diastolic blood pressure, fasting blood glucose, alanine aminotransferase, triglyceride, and high-density lipoprotein cholesterol, showed that the prevalence risk of NAFLD was increased significantly according to the monocyte fraction quartiles: odds ratios (ORs) and 95% confidence intervals (CIs) for NAFLD were 1.00, 2.75 (1.63-4.62), 2.84 (1.67-4.84) and 5.17 (3.03-8.83), respectively. There were no significant associations between NAFLD and the total WBC count quartiles in this model. These results indicate that the elevated peripheral blood monocyte fraction is associated with NAFLD. The monocyte fraction might be a useful marker for NAFLD.