question: OBJECTIVES: To characterise the clinical features and to discover predictive factors of adult males with nocturnal enuresis (NE). PATIENTS AND METHODS: A total of 43 eligible adult male patients (mean age was 57.8 years) were recruited prospectively over a 2‐year period. After documentation of medical history, lower urinary tract symptoms (LUTS) were assessed using the International Consultation on Incontinence Modular Questionnaire‐male LUTS (ICIQ‐MLUTS), and a 3‐day ICIQ‐bladder diary (ICIQ‐BD). Video‐urodynamic studies (VUDS) were conducted conforming to the International Continence Society standards. Univariate and multivariate linear regressions were performed to determine potential predictive factors. RESULTS: Patients with NE had a variety of LUTS and had a high incidence of obesity and comorbidities. On the ICIQ‐BD, NE was associated with nocturnal polyuria (NP), reduced nocturnal bladder capacity (NBC), or a combination of both. Subgroup analysis indicated that patients with more frequent NE had: higher body mass index (BMI); more comorbidities; reduced daytime urinary frequency and urgency quality of life (QoL) sub‐scores; and increased stress urinary incontinence (SUI) and nocturnal bedwetting sub‐scores. Patients with reduced NBC only, had fewer NE episodes, while patients with NP, or with both NP and reduced NBC were more likely have frequent NE. Multivariate analysis confirmed that: BMI; neurogenic causes; sub‐scores of SUI QoL and bedwetting domain; the presence of reduced NBC, and both NP and reduced NBC; and bladder outlet obstruction, were all independent predictive factors for the severity of NE. CONCLUSIONS: NE n the adult male should be systemically assessed and treated, as obesity, neurogenic disorders, excessive urine production, bladder storage and emptying dysfunctions are risk factors. Bladder diaries and VUDS provide valuable information on potential pathophysiological causes, which could assist clinical evaluation and selection of focussed treatment.