Several mutations of the pituitary-specific transcription factor Pit-1 have been identified. We describe a girl with a mutation of the Pit-1 gene leading to a complete lack of GH, TSH and prolactin and a marked hypoplasia of the anterior pituitary gland. The patient had a homozygous nonsense-mutation at position 172 (CGA to TGA), converting arginine into a stop codon, leading to an early termination of protein translation. During the infancy period the girl had very conspicuous symptoms of hypothyroidism and the diagnosis of thyroid insufficiency preceded the diagnosis of GH-deficiency by 1.5 years. Treatment with thyroxine and GH resulted in excellent catch-up growth.