objectives: nocturia is a frequent urinary symptom in overactive bladder (oab) patients, which usually exerts a negative impact upon their quality of life. this study describes the profile of the oab patient with nocturia, in order to contribute to the adequate identification and medical management of these subjects. methods: multicenter, national observational study of 1454 patients over 18 years of age,previously diagnosed with oab. the relationship between nocturia and different personal and clinical variables was studied, and logistic regression models were used to identify variables independently associated with nocturia in both women and men. results: 84.6% of the patients presented nocturia, considering the restrictive criterion of two or more micturition episodes per night (96.8% according to the ics definition). urinary symptoms of frequency, urgency and urge incontinence were associated in a bivariate analysis with nocturia for both genders, while the voiding difficulty variable "pain" was only associated in women, and the voiding difficulty variable "straining" only in men. older age and presence of comorbidities were associated both in bivariate analysis and independently in logistic regression models to the presence of nocturia in oab patients of both genders. conclusions: this study revealed that the profile of subjects with previously diagnosed oab and nocturia corresponded to older age and the presence of comorbidities of a certain impact for both men and women. the profile for oab patients with nocturia differs from those previously reported for patients suffering from nocturia and other urinary pathologies.