For a study, researchers sought to understand that the prevalence of nocturnal polyuria (NP), or nocturia brought on by excessive urination while sleeping, is mostly restricted to men and varies depending on how the condition was defined. This epidemiological study of men and women over 30 years old from the United States evaluated the prevalence of NP. Willing individuals completed the baseline EpiNP (Epidemiology of Nocturnal Polyuria) survey (e.g., Lower Urinary Tract Symptoms Tool, comorbidities). Investigators invited 100 randomly chosen respondents who reported 0 or 1 void per night and everyone else who reported more than 2 voids/night to complete 3-day bladder diaries. Nocturnal polyuria index (NPI) of more than 0.33 (NPI33) and nocturnal urine production of more than 90 ml/hour were used to characterize NP (NUP90). Extrapolated prevalence was broken down into subgroups based on sex and idiopathic (without underlying reasons), overactive bladder (NPOAB), bladder outlet obstruction (NPBOO; men), and comorbidities. Each subgroup’s voiding patterns and timing were evaluated, including the start of unbroken sleep. The baseline survey was completed by 10,190 people, with a mean age (interquartile range) of 54.4 (30-95). A total of 3,938 people were invited to participate in the diary; 1,763 of them (49.5%) finished the 3-day version. Both men and women with idiopathic NP and comorbidities had increased pee production (maximum nighttime volume, total volume, nocturnal urine production, and nocturia score). NPBOO in males and NPOAB in women had the highest median number of nocturnal voids. Nighttime voiding-related anxiety varied by NP subgroup, but it was highest in NPBOO for males (NPI33: 69.6%; NUP90: 71.1%) and NPOAB for women (NPI33: 67.5%; NUP90: 66.0%). Focusing on factors impacting pee production as opposed to factors influencing bladder capacity, this population-based study on nocturia prevalence, which included both men and women, identifies nocturia subgroups and offers insights into nocturia treatment.