This study was intended to achieve a linguistic adaptation and validation into Spanish of the LANNS scale for the differential diagnosis of neuropathic pain. Cross-sectional validation study carried out in two phases: first, cultural adaptation into Spanish language, by means of a conceptual equivalence approach, including forward and backward translations in duplicate and review by experts; and second, validation study of the scale in patients with neuropathic, noniceptive and mixed pain, in which the scale properties of reliability (internal consistency and inter-rater agreement with kappa and intra-class correlation coefficients) and validity (ROC curves analisys, agreement with reference diagnosis and determination of sensitivity, specificity and positive and negatives predictive values) were evaluated. A total of 156 subjects (90 women, 58.4%), 89 with pain of neuropathic origin (mean age [SD], 59.6 [19.4] years, 22 with mixed pain due to radiculopathy) and 67 with nociceptive pain (66.6 [11.8] years) were included in the study. Diagnosis of the type of pain was performed by standard clinical criteria. The scale was administrated by trained interviewers, in duplicate and blinded to the reference diagnosis. The scale showed good reliability (internal consistency: Cronbach and Guttman split-half coefficients between 0.68 and 0.71; inter-rater agreement: kappa coefficient of 0.70 and intra-class correlation coefficients between 0.77 and 0.92) and validity for a cut-off value > or = 12 points, which represented the best value to discriminate between patients with neuropathic and nociceptive components of pain (kappa coefficient = 0.70; CI 95%, 0.59-0.81; p < 0.0001); area under the curve, 0.929; (p < 0.0001); specificity, 89.4% (CI 95%, 79.4%-95.6%) and positive value, 91.1%; CI 95%, 82.6%-96.4%). The Spanish version of the LANSS scale is reliable and valid for the differential diagnosis of neuropathic pain.