Quality of life (QoL) has emerged as an end point in the evaluation of adults with growth hormone deficiency and acromegaly. QoL is measured with questionnaires designed to be used in general population or any kind of disease (generic) or aimed at the specific dimensions affected in a determined condition; these latter ones are more likely to identify the impairments caused by the underlying disease and the benefits of treatment. QoL, which is severely impaired in adults with growth hormone deficiency, improves and normalizes after growth hormone replacement therapy and this effect is maintained over several years. Acromegalic patients also exhibit severe impairment of QoL, which despite improvement after successful therapy still remains below the reference values of normal population. QoL in these chronic endocrine diseases can be used as an measure for clinical and therapeutic evaluation.