Objectives:Our primary aim was to determine bowel and bladder function in children aged 1 month to 7 years in the general Dutch population. Second, we aimed to identify demographic factors associated with the presence of bowel and bladder dysfunction, and their coexistence.Methods:For this cross-sectional, population-based study, parents/caregivers of children aged from 1 month to 7 years were asked to complete the Early Pediatric Groningen Defecation and Fecal Continence questionnaire. Different parameters of bowel and bladder function were assessed using validated scoring systems such as the Rome IV criteria.Results:The mean age of the study population (N = 791) was 3.9 ± 2.2 years. The mean age at which parents/caregivers considered their child fully toilet-trained was 5.1 ± 1.5 years. Prevalence of fecal incontinence among toilet-trained children was 12%. Overall prevalence of constipation was 14%, with a constant probability and severity at all ages. We found significant associations between fecal incontinence and constipation [odds ratio (OR) = 3.88, 95% CI: 2.06–7.30], fecal incontinence and urinary incontinence (OR = 5.26, 95% CI: 2.78–9.98), and constipation and urinary incontinence (OR = 2.06, 95% CI: 1.24–3.42).Conclusions:Even though most children are fully toilet-trained at 5 years, fecal incontinence is common. Constipation appears to be common in infants, toddlers, and older children. Fecal incontinence and constipation frequently coexist and are often accompanied by urinary incontinence. Increased awareness of bowel and bladder dysfunction in infants, toddlers, and young children is required to prevent these problems from continuing at older ages.