OBJECTIVE.- To analyze the prevalence of cognitive function impairment (CI) in patients with neuropathic pain (NeP). METHODS: Cross-sectional analysis of a sample of patients with NeP enrolled in a naturalistic, multicenter study evaluating the effectiveness of gabapentin in NeP. A total of 1519 patients (58.8% women) aged °Ý18 years [mean age (SD) = 56.0 (13.7) years], with NeP or mixed (neuropathic and nociceptive) pain (MP) for 1.1 (2.8) years, were enrolled in the study. Pain was assessed with the McGill sort-form questionnaire, and cognitive function with the Mini Mental State Examination ¨CMMSE- [a score °Ü24 was considered as cognitive impairment (CI)]. Multivariate logistic regression models were used to estimate CI prevalence. RESULTS: CI was substantially higher in patients with NeP than that reported in the general Spanish population, and significantly higher than in MP patients: 6.1% (4.0% - 8.8%) versus 1.6% (0.7% - 3.1%), p <0.001 [adjusted OR = 4.36 (1.92 - 9.92)]. Prevalence significantly increased with age up to 28.3% (16.8% - 42.4%) in NeP, and to 20.0% (7.7% - 38.6%) in MP for the age groups °Ý75 years, p <0.001. Patients with peripheral diabetic neuropathy and central post-stroke pain had significantly higher prevalence than other groups. CI was significantly associated to pain severity in NeP patients. CONCLUSIONS: Despite the limitations observed, this evaluation showed that after adjusting by confounders the prevalence of cognitive impairment was substantially higher in patients with NeP as compared to MP and the reference general population. Age, diabetic neuropathy, and central post-stroke pain were factors found significantly associated to cognitive impairment.