Steroids are the cornerstone of the treatment of childhood nephrotic syndrome. The optimal duration for the first episode remains a matter of debate. The aim of this study is to determine whether the 8 weeks International Study of Kidney Disease in Children (ISKDC) regimen is equally effective as the 12 weeks steroid regimen from the German society of pediatric nephrology (Arbeitsgemeinschaft für Pädiatrische Nephrologie [APN]). An individual patient data (IPD) meta-analysis of randomized controlled trials reporting on prednisolone treatment for a first episode of childhood nephrotic syndrome was conducted. European trials aimed at investigating the ISKDC and/or APN steroid regimen were selected. The lead investigators of the selected trials were requested to provide the IPD of the specific treatment groups. Four trials included European cohorts using dosing schedules according to the regimens studied. IPD of two trials were available. A significant difference was found in time to first relapse after cessation of steroid treatment between the 8 and 12 weeks treatment group with a median time to relapse of 29 and 63 days, respectively. Moreover, relapse rate ratios during total follow-up were 51% higher for the 8 weeks regimen. Finally, younger children have a significantly lower time to first relapse and frequently relapsing nephrotic syndrome. Conclusions: The results of this IPD meta-analysis suggest that the 8 weeks steroid regimen for a first episode of steroid-sensitive nephrotic syndrome may not be equally effective as the 12 weeks steroid regimen. Moreover, this study highlights the importance of using uniform definitions to enable accurate comparison and interpretation of trial results. Trial registration: Registration number: CRD42020199244, date of registration 16-08-2020What is Known:• Steroids are the cornerstone of the treatment of childhood nephrotic syndrome, however the optimal duration for the first episode remains a matter of debate.• Currently, the 8 weeks ISKDC protocol and 12 weeks APN protocol are among the most frequently used protocols in Europe.What is New:• The 8 weeks steroid regimen for a first episode of steroid-sensitive nephrotic syndrome may not be equally effective as the 12 weeks steroid regimen for the treatment of a first episode of nephrotic syndrome.• Younger children have a significantly shorter time to first relapse and time to frequent relapsing nephrotic syndrome.