Objectives: to construct and validate a classification of nipple and areola complex lesions resulting from breastfeeding, according to content and appearance.
Methods: this is a methodological study, developed in four stages: operational definition, instrument construction, content and appearance validation. The Delphi technique and a Likert-type scale were used to validate content and appearance, through the participation of ten and sixteen judges, respectively. For analysis, Content Validity Index and Kappa Coefficient were applied.
Results: Content Validity Index obtained an overall value of 0.93 and, for appearance, 0.94. Kappa values ranged between 0.46 and 1. The high rates of agreement among judges demonstrated the quality of the proposed content validity.
Conclusions: the Nipple and Areola Complex Lesions Classification Instrument developed obtained acceptable values of its indexes, proving to be valid in terms of content and appearance.