Background: Growth hormone deficiency is a rare condition in which the body does not make enough growth hormone. Incidence of child-onset GHD is approximately 1:4,000 to 1:10,000 live births. GH is essential for normal growth, muscle and bone strength, and distribution of body fat. The aim of study is to study the effect of growth hormone treatment on growth velocity during the first two years of treatment in children with growth hormone deficiency. Patients and Methods: A retrospective study conducted at pediatric endocrinology outpatient clinic in children welfare teaching hospital/medical city in Iraq from 1st of November 2017 to thirty of October 2019 because of short stature due to GHD. Included 248 patients with GHD on growth hormone replacement of the following data were collected from the file records of the patients included in the research; name of patients, weight, height, sex of patients, bone age, growth velocity and age at the time of onset of the complaint and starting treatment. After the initiation of GH treatment, all patients were observed for height and weight with each visit, GV and BA after one and two years of treatment. Results: The most common age of presentation was >10 years for male and female patients; most of them were males. For male patients; after the first and second year of treatment, the mean height velocity showed good response to GH treatment. For female patients; the mean height velocity also increased during the first and second years of treatment. Conclusion: GH therapy for short stature due to GHD is safe and effective for all pediatric age groups before bone closure.