Four male Pomeranians that showed alopecia with an age of onset between five months and eight years were investigated. The aim of the investigation was to clarify whether the affected dogs had alopecia X and whether their symptoms might be due to a hereditary defect. The four affected dogs showed hairless patches at the root of the tail, at the back, at the limbs from the thigh to the tarsus and at the abdomen. Within the hairless patches some islets with sparse hair were present. In hairless patches the skin was dark pigmented. Besides the alopecia and hyperpigmentation no other symptoms were found according to anamnestic and clinical examination. History, clinical examinations, laboratory diagnostics, and histopathology of skin biopsies allowed the diagnosis of alopecia X in three affected male dogs. The last one of the affected dogs additionally had slightly reduced thyroid hormone levels. Based on identical symptoms and the close relatedness of all four animals, it was assumed that the fourth affected dog also had alopecia X. The available data possibly indicate a monogenic autosomal dominant inheritance, however a recessive inheritance can not be excluded at this time.