Objectives: The objective of this pilot study was to develop and validate an electronic height based weight estimation device (Rolling tape) for Korean children. Methods: We obtained body weight and age data from a survey conducted by the Korean Pediatric Society in 2005, which was performed to establish normative values for Korean children. Using those data, an electronic height-based weight estimate device ‘( Rolling tape’) was developed with the data from more than 90,000 Korean children. The Rolling tape measure height of a patient by rolling the roller at the one end of the device alongside a patient, from head to heel. After the measurement of height by rolling, the measured height was transferred to a personal computer via wireless communication (Bluetooth?). Then, the personal computer processed and converted the measured height into the several important variables, such as the dose of epinephrine and the size of endotracheal tube for the subject. The final outcome variables were automatically printed out and shown on a monitor. For validation of this device, we enrolled patients visiting pediatric emergency department of Seoul National University Hospital for any reasons. After enrollment, the actual height and weight was measured and then two researchers were estimated the height and weight with the Rolling tape at 5-minutes intervals. The inter-rater reliability among the three numbers (actual values, estimated with roller tape by researcher 1 and 2) were analyzed by inter-observer correlation coefficient (ICC). Results: A total of 43 patients were enrolled. The median age was 44 months (IQR 25 to 92) and male was 20 (46.5%). The weight and height of one patient was below 5 percentile and that of another 42 patients was between 5 and 95 percentile. The range of actual weight was from 9 to 51 Kg and that of actual height was from 61 to 141 cm. There were significantly similar values of the height among three categories (ICC=0.983, p<0.001). The estimated weight and height measured by two researchers are significantly correlated with actual weight (ICC=0.958, p<0.001). Conclusion: We developed and validated an electronic device to estimate weight-based height of children. We found that this new device was well correlated with actual height and weight in a pilot study.