A 40-year-old man presented with acromegaly, reduction of visual acuity and visual field, and elevated blood sugar. Imaging examinations demonstrated a large sellar adenoma with suprasellar extension that compresses the optic chiasma upward, spreads downward to the sphenoid sinus, and invades the cavernous sinus bilaterally. Random prolactin and growth hormone were beyond the scope of normal. The patient achieved complete shrinking of the adenoma by taking bromocriptine orally. For some kinds of giant mixed growth hormone-prolactin adenomas, surgical treatment is not necessary, and drug treatment can also achieve good results.