Rumination disorder was initially documented as affecting newborns, infants, children and individuals with mental and functional disabilities (the cognitively handicapped). It has since been recognized to occur in both males and females of all ages and cognitive abilities.

Among the latter, it is described with almost equal prevalence among infants (6–10% of the population) and institutionalized adults (8–10%).  In infants, it typically occurs within the first 3–12 months of age.

The occurrence of rumination syndrome within the general population has not been defined.Rumination is sometimes described as rare, but has also been described as not rare, but rather rarely recognized. The disorder has a female predominance. The typical age of adolescent onset is 12.9, give or take 0.4 years (±), with males affected sooner than females (11.0 ± 0.8 for males versus 13.8 ± 0.5 for females).

There is little evidence concerning the impact of hereditary influence in rumination syndrome. However, case reports involving entire families with rumination exist.