Several studies have shown that general and specific cognitive dysfunction may be present during the early stages of chronic kidney disease. These studies, however, were conducted in elderly patients with comorbid conditions and used a limited battery of cognitive tests. Here we determined whether 40- to 54-year-old women in a population-based cohort in Taiwan with moderate chronic kidney disease have reduced cognitive performance. In total, 64 women with moderate chronic kidney disease (estimated glomerular filtration rate (eGFR) stage 3) were randomly matched by age and education with 192 control individuals with eGFR stage 2 or better. All patients underwent the Rey Auditory-Verbal Learning Test, visual memory, verbal fluency, Trail Making Test, digit spans, and Hospital Anxiety and Depression Scale neuropsychological tests. Women with moderate chronic kidney disease had significantly worse performance in delayed recalls and backward digit span than controls. Mixed effects modeling showed that women with moderate chronic kidney disease had reduced cognitive performance after controlling for body mass index, menopausal status, and psychosocial distress. Thus, in a population-based sample, we found that midlife women have reduced cognitive performance associated with early-stage chronic kidney disease. If confirmed, routine cognition evaluation of patients with mild chronic kidney disease may help identify this problem earlier because mild cognitive impairment can convert to dementia.