This review addresses the prevalence of hypochondriasis and less restrictive subtypes of hypochondriacal phenomena (abridged hypochondriasis and health anxiety). Altogether, 55 papers based on 47 independent samples reporting prevalence rates of hypochondriasis, abridged hypochondriasis, and health anxiety were taken into account. Investigations of the general population, general medical samples (e.g., primary care) and specific clinical samples (e.g., cancer patients) were included in the present review. In general populations a weighted prevalence of 0.40% was found for hypochondriasis (range 0.0–4.5%) and a weighted prevalence of 1.00% (0.6–2.0%) was found for abridged hypochondriasis. Health anxiety was frequently reported in general populations with a wide range (2.1–13.1%). In general medical samples a weighted prevalence rate of 2.95% (range 0.3–8.5%) was found for hypochondriasis. Abridged hypochondriasis was only reported in one study; however, the prevalence of abridged hypochondriasis was three times higher than the full diagnostic criteria of hypochondriasis. In specific clinical samples (e.g., cancer patients, psychiatric outpatients) hypochondriasis and health anxiety were frequently reported as well. Comparisons of persons with the full hypochondriasis diagnosis and abridged hypochondriasis show large similarities regarding psychopathological characteristics and clinical impairment, which underline the importance of a less restrictive definition of hypochondriasis considered in DSM-5. Findings regarding potential risk factors were very inconsistent and no clear risk factors could be identified. The high prevalence of hypochondriasis in medical settings should be addressed in the future with effective screening instruments in order to optimize treatment strategies for patients with hypochondriasis and persons with elevated health anxiety.