Summary Due to the positive effects demonstrated in randomized clinical trials on cardiovascular surrogate markers and bone metabolism, a positive effect of growth hormone (GH) treatment on clinically relevant end-points seems feasible. In this review, we discuss the long-term efficacy and safety of GH treatment in adult patients with growth hormone deficiency (GHD) with emphasis on morbidity: fatal and nonfatal cardiovascular disease (CVD) and stroke, fractures, fatal and nonfatal malignancies and recurrences, and diabetes mellitus. A positive effect of GH treatment on CVD and fracture risk could be concluded, but study design limitations have to be considered. Stroke and secondary brain tumours remained more prevalent. However, other contributing factors have to be taken into account. Regrowth and recurrences of (peri)pituitary tumours were not increased in patients with GH treatment compared to similar patients without GH treatment. All fatal and nonfatal malignancies were not more prevalent in GH-treated adults compared to the general population. However, follow-up time is still relatively short. The studies on diabetes are difficult to interpret, and more evidence is awaited. In clinical practice, a more individualized assessment seems appropriate, taking into consideration the underlying diagnosis of GHD, other treatment regimens, metabolic profile and the additional beneficial effects of GH set against the possible risks. Large and thoroughly conducted observational studies are needed and seem the only feasible way to inform the ongoing debate on health care costs, drug safety and clinical outcomes. © 2014 John Wiley & Sons Ltd.