The use of recombinant human growth hormone (rhGH) in patients with idiopathic short stature (ISS) has been an area of concern since some studies reported less desired effects of the drug in this group of patients as compared to patients with growth hormone deficiency (GHD). In addition, there were no studies addressing the effects of rhGH in Saudi children. Therefore, we conducted a retrospective study to observe the effects one year of treatment with rhGH on the mean height gain in patients with ISS and GHD. Methods This retrospective study took place at King Abdulaziz Medical City in Jeddah. The study subjects included two groups of patients (GHD vs ISS). Patients' files were reviewed from January 2000 to January 2018 using the following parameters: chronological age, bone age, height, weight, body mass index (BMI), insulin-like growth factor (IGF-1), growth hormone stimulation test, and growth velocity (GV). After one year of treatment, the height, weight, and BMI of the study subjects were monitored and assessed.