Abstract Disclosure: H. Lee: None. S. An: None. M. Cho: None. H. Nam: None. Objective: The aim of this study was to assess the final adult height (FAH) achieved through recombinant human growth hormone (GH) treatment and the factors influencing FAH. Methods: We retrospectively reviewed the charts of all patients diagnosed with IGHD who were prepubertal when they began GH treatment since August 2007. FAH was determined in 41 patients (28 males and 13 females) by July 2023. Results: 41 patients started treatment at an average age of 9.1 years and continued for 6.5 years. The mean initial height was -2.6 standard deviation scores (SDS) and the mean FAH was -0.6 SDS. GH treatment was initiated at a significantly younger age in females than in males (7.2±1.9 vs 10.0±3.2; p=0.01). The mean FAH was 169.9±4.5cm for males and 156.1±3.2cm for females. Differences between initial height and final height SDS were not significant between males and females. The mean of FAH SDS was higher compared to their mid-parental height -1.0 SDS (p=0.017). In multiple regression analysis, FAH showed a positive correlation with initial height, duration of treatment, and growth rate in the first year of treatment, and a negative correlation with BMI SDS at the start of GH (r2=0.59; p=0.000). FAH SDS was positively related to initial height SDS and growth rate in the first year of treatment. (r2=0.3; p=0.001) Conclusions: The mean FAH SDS after GH treatment was significantly higher than the mean MPH SDS in IGHD patients. Moreover, the good response of GH treatment was associated with longer treatment duration, greater height at the start of treatment, better treatment response at 1 year, and lower initial BMI SDS. Presentation: 6/3/2024