Abstract Context: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy is known as a rare hereditary disease with classic triad of mucocutaneous candidiasis, hypoparathyroidism, and adrenocortical failure, two of which, diagnostic dyad, are required for the diagnosis. Evidently many patients suffer unrecognized because the condition is more variable and complex. Objective: The objective of the study was to describe the variability of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy for promoting recognition and adequate follow-up of patients. Setting: The Finnish series of patients is the largest internationally. Patients: The study population was all 91 known Finnish patients. Results: Besides the classical triad, a dozen autoimmune endocrine and other components occurred variably, several of them dangerous. The initial manifestation appeared within the age range of 0.2–18 yr, mucocutaneous candidiasis being part of it in 60% of the patients, hypoparathyroidism in 32%, and adrenocortical failure in 5%. But 23% of the patients had one to six other components before the diagnostic dyad: hepatitis, keratoconjunctivitis, chronic diarrhea, periodic rash with fever. The dyad appeared 0.2–20 yr later. Prevalence of most components increased with age, diabetes mellitus, hypothyroidism, and testicular failure becoming common toward middle age. Tubulointerstitial nephritis occurred in 9% of the patients, apparent mineralocorticoid excess in 9%, asplenia in 19% of adults, and oral or esophageal squamous cell carcinoma in 10% of patients older than 25 yr. Conclusions: Any child or young adult with one of the many disease components should be examined for others and consideration of AIRE mutation assay.