A 56-year-old acromegalic patient was treated with conventional radiotherapy. One year after treatment, the patient's growth hormone level was normal and remained so for a full year. Subsequently, the growth hormone level returned to the pretreatment, acromegalic range. The attainment of a normal growth hormone level after treatment of acromegaly is no assurance that the level will remain normal. Repeated growth hormone level determinations are necessary before cure can be considered permanent.