Introduction Pituitary tumors secreting growth hormone (GH) are relatively rare in children and adolescents. Giant ones (maximal diameter ≥ 4 cm) are even rarer. We aimed to analyze their frequency and their complications in Algerian population. Methods It is a retrospective and multicenter study over a long period of time (1980–2013) which aimed to collect giant pituitary tumors secreting GH in order to analyze their characteristics. Results Among 31 well proved somatotroph adenomas observed in children and adolescents (≤ 20 years old) or in older subjects with lack of pubertal development, we found 12 giant tumors = 38.7%. Median age at diagnosis was 22.4 years old (13–30). Eight on 12 suffered from gigantism (66.6%) other had acromegaly. Median tumor diameter = 60.5 mm (40–100). Median GH = 570 ng/mL (30–1430). All had moderate to severe visual troubles. Two or more pituitary deficits were observed in 4 cases = 33.3%, hydrocephalus = 8 cases (66.6%), frontal syndrome = 3 = 25% and epilepsy n = 1 = 8.3%. Conclusion In our population giant tumors secreting GH are frequent and diagnosed late even in those with gigantism which explains the high frequency of severe and life threatening neurological complications.