Background The prevalence of hidradenitis suppurativa (HS) in Asia is unknown. The associations between HS and other autoimmune disorders have rarely been reported. Objective We sought to determine the prevalence of and diseases associated with HS using the National Health Insurance (NHI) database. Methods We examined Korean NHI claim database data from 2007 to 2016. We enrolled all patients with HS and age‐ and sex‐matched control subjects without HS. We estimated the period prevalence of HS and associated comorbidities in Korea. Results We identified 28 516 patients with HS (61.3% males and 38.7% females). The period prevalence rate was 0.06%, 55.8 patients (95% confidence interval 55.1–56.4) per 100 000 persons, and the female‐to‐male ratio was 1 : 1.6. HS patients were at significantly increased risk of rheumatoid arthritis, ankylosing spondylitis, type 1 diabetes, ulcerative colitis, type 2 diabetes, hypertension, hyperlipidaemia, acne conglobata, pilonidal cysts, psoriasis, pyoderma gangrenosum, alopecia areata and vitiligo. Conclusion The overall prevalence of HS in Korea was lower than that in Western populations, and male patients predominated. Linked article: This article is commented on by G.B.E. Jemec, p. 1625 in this issue. To view this article visit https://doi.org/10.1111/jdv.15220