Fibromyalgia Syndrome (FMS) is a frequent idiopathic condition in which patients experience intense pain in specific tender points, profound fatigue and sleep disturbances. Although pain had not account so far in growth hormone deficiency syndrome (GHD) description, symptoms of FMS are very similar; and there is strong evidence of decreased GH secretion at least in a subset of FMS patients. Is there an overlap of the two diseases? A systematic Medline/Embase search for preliminary proof-of-concept trials, but also larger placebo-controlled studies, have shown that GH replacement in low-IGF1 patients can significantly improve some symptoms of FMS and quality of life, suggesting a direct causal effect of GH deficiency. Despite the use of relatively high doses of GH in these patients, treatment seems to be well tolerated. Several mechanisms of action for GH in FMS relief have been suggested, including both central modulation of pain and peripheral musculo-tendinous effects, as already described in classic GHD.