Objectives <p>The relationship between abdominal obesity and cognitive impairment is not fully understood. The lipid accumulation product (LAP) is a convenient and cost-effective indicator for abdominal obesity. In the present study, we investigated the association between the LAP and cognitive impairment in a community-based 4-year prospective cohort study.</p> Methods <p>A total of 1349 (≥ 40 years) participants without cognitive impairment from the village of Xi’an, China were followed for 4 years. Cognitive impairment was diagnosed using a three-step protocol. The LAP was calculated using waist circumference and serum triglyceride levels. Multivariate logistic regression analysis and interaction analysis were used to assess the relationship between the LAP and cognitive impairment.</p> Results <p>The mean age of the participants at baseline was 55.0 ± 9.3 years, 816(60.5%) were female, and 46 (3.4%) were diagnosed as cognitive impairment during the 4-year follow-up. Multivariate logistic regression analysis revealed that lnLAP was not associated with the cognitive impairment in the total population. After stratification by sex, cognitive impairment was associated with lnLAP (OR = 1.85, 95% CI: 1.058–3.257, <i>P</i> = 0.031) in females but not in males (OR = 1.142, 95% CI: 0.503–2.594, <i>P</i> = 0.751). In the females, cognitive impairment was 4.09-fold greater in the highest LAP quartile than that in the lowest LAP quartile (OR = 4.098, 95% CI: 1.135–14.792, <i>P</i> = 0.031).</p> Conclusion <p>High LAP was associated with cognitive impairment in females but not in males. These findings indicate that the effects of abdominal obesity on cognitive impairment may differ between males and females.</p>