Objective: Half a century ago the prevalence of Sheehan's syndrome (SS) was 10-20 per 100,000 women. With better obstetric help the prevalence is assumed to have decreased, especially in developed countries. Design: We studied the prevalence of SS in 2009 in a nationwide retrospective population-based study. Methods: All patients with diagnosed SS were identified, and information regarding obstetric care, clinical presentation and hormonal assays was collected. Correlation was calculated with Kendall's-tau b. Significance level: p1000 ml). Six had complicated deliveries. The most common clinical presentation was failure to lactate and failure to resume menstruation. The patients had three to five failing pituitary axis. There was no correlation between bleeding at delivery or the number of hormonal axes affected and DD. Conclusion: The prevalence of SS in Iceland was higher than we expected in a country with modern obstetric care. Long DD and incidental diagnosis indicate that women might be lacking correct diagnosis and treatment, and thus the prevalence of SS is even higher. As SS is easily diagnosed and treatable, but can be life-threatening if unrecognised, doctors need to be aware of the disease.