Data on sex differences in acromegaly at the time of diagnosis vary considerably between studies.A nationwide cohort study including all incident cases of acromegaly (1978-2010, n=596) and a meta-analysis on sex differences in active acromegaly (40 studies) were performed.Sex-dependent differences in prevalence, age at diagnosis, diagnostic delay, pituitary adenoma size, insulin-like growth factor 1 (IGF-I), and growth hormone (GH) concentrations were estimated.The cohort study identified a balanced gender distribution (49.6% females) and a comparable age (years) at diagnosis (48.2 CI95% 46.5-49.8 (males) vs. 47.2 CI95% 45.5-48.9 (females), p = 0.4). The incidence rate significantly increased during the study period (R2 =0.42, P<0.01) and the gender ratio (F/M) changed from female predominance to an even ratio (SR: 1.4 vs. 0.9, P=0.03). IGF-ISDS was significantly lower in females compared to males, whereas neither nadir GH nor pituitary adenoma size differed between males and females. In the meta-analysis the weighted percentage female was 53.3% (CI95% 51.5-55.2) with considerable heterogeneity (I2 =85%) among the studies. The mean age difference at diagnosis between genders was 3.1 years (CI95% 1.9-4.4) and the diagnostic delay was longer in females by 0.9 years (CI95% -0.4-2.1). Serum IGF-I levels were significantly lower in female patients, whereas nadir GH, and pituitary adenoma size were comparable.There is only a minor sex differences in the epidemiology of acromegaly at the time of diagnosis except that female patients are slightly older and exhibit lower IGF-I concentrations and a longer diagnostic delay.