To evaluate the long-term effectiveness of weekly vs. daily growth hormone (GH) administration in children with GH deficiency. This study, part of the "LG Growth Study", included a total of 996 children with GH deficiency (773 receiving daily GH and 193 receiving weekly GH). Anthropometric data were collected at baseline and every 12months; clinical and laboratory data were collected at baseline and throughout the study. At baseline, the weekly GH group was older, shorter in mid-parental height (MPH), and had more pubertal boys compared to the daily GH group (age: 8.46±3.44 vs. 7.46±2.89 years, p<0.001; MPH:-0.88±0.73 SD vs.-1.02±0.84 SD, p=0.044; pubertal boys: 34.0 vs. 16.9 %, p=0.006). Height velocity and change in height SDS during the first 12months were higher in the daily GH group (height velocity: 9.06±1.72 vs. 8.67±1.98 cm/year, p=0.028; height SDS change: 0.78±0.39 vs. 0.61±0.41, p<0.001). However, height SDS at 24 and 48months were similar between groups. No significant differences in overall height velocity, annualized treatment continuation rate, and safety profile were observed over 48months. Weekly GH therapy appears to be an effective and safe alternative to daily GH treatment in children with GH deficiency over a 4-year period. Further research with larger sample sizes and longer follow-up is needed to confirm these findings and assess the extended safety and effectiveness of LAGH.