Currently, the in-vitro method has been recognized as the valid gold standard for Nuclear Medicine. However, bloodletting is necessary in the use of this method and cold be very traumatic, most especially for pediatric patients. The Inoue method bypasses this trauma by omitting the need to withdraw blood. The study consisted of 36 patients ranging from ages 2 months to 19 years old. The subjects used were those who were previously subjected to in-vitro method. The scintigrams of the in-vitro method would be obtained and processed for split percentage uptake and for parameters needed to obtain Inoue GFR. The first set of data for total percentage uptakes versus normalized in-vitro GFR obtained are observed that percent renal uptakes are proportional to in-vitro GFR. The main data set of this paper of this paper, correlates the Inoue GFR and the reference method (in-vitro method), which has a significantly strong correlation (r=0.926). Thus, Inoue method is a viable, simple, and practical technique in determining GFR in pediatric patients, since it yields a precise value as the clinical gold standard.