In autoimmune hypothyroidism (Hashimoto's disease), TPO (thyroid peroxidase) antibodies may be detected, while in autoimmune hyperthyroidism (Graves' disease) thyroid-stimulating hormone (TSH ) receptor antibodies (TSH -R-AB s) are frequently present. Less well known is the fact that autoimmune hypothyroidism can present with TSH-R-ABs and ophthalmic Graves' disease (OGD). This condition is also known as hypothyroid Graves' disease. In this report we describe four patients with this uncommon phenomenon. These four cases demonstrate that differences between Hashimoto and Graves' disease are less clear than expected. Hypothetically the thyroid cell might be 'attacked' by blocking and stimulating antibodies. Dependent on the relative concentrations, hypothyroidism or hyperthyroidism may occur. So the differences between Hashimoto's disease and Graves' disease, at least in these cases, may be gradual and small.