This observational and descriptive study was carried out to validate the nursing diagnoses Sexual Dysfunction and Ineffective Sexuality Pattern and relate the relevance of the defining characteristics validated by experts with their incidence in patients. Validation by experts involved 32 specialists and 20 patients to verify clinical evidence. For the diagnosis Sexual Dysfunction, the experts attributed scores higher than 0.80 to seven defining characteristics; for Ineffective Sexuality Pattern, four characteristics received scores between 0.50 and 0.80. The clinical occurrence of these characteristics for the Sexual Dysfunction diagnosis ranged between 55% and 90% of the sample and, for Ineffective Sexuality Pattern, between 30% and 85% of the sample. The study contributed to the improvement of these diagnoses and to careful consideration on their defining characteristics according to experts and as observed in a given clientele.