Background: Neonatal jaundice is a frequent benign condition in newborns. However, a rapid diagnosis must be established for its most appropriate treatment. The objective of this study was to measure the correlation between total serum bilirubin (TSB) and transcutaneous bilirubin (in forehead and sternum) in full-term newborns at 3400 m above sea level. Methods: We conducted a prospective and cross-sectional study in full-term newborns with clinical jaundice from the Hospital Regional in Cusco-Peru. General characteristics and measurement of TSB, transcutaneous forehead bilirubin (TcBF), and transcutaneous bilirubin in the sternum (TcBS) were explored. Correlation, sensitivity, and specificity were calculated. Receiver operating characteristic (ROC) curves were constructed using the SPSS statistical package, version 22.0. Results: A total of 123 newborns were evaluated. The mean bilirubin values were 13.7 ± 3.5 for TcBF, 14.1 ± 3.1 for TcBS, and 13.8 ± 3.9 for TSB. In addition, Pearson correlation coefficients between TSB/TcBF and TSB/TcBS were 0.90 and 0.91, respectively (p < 0.001). For the percentile 95 cut-off point, a sensitivity of 93% and 100% and a specificity of 89% and 80% were obtained for TcBF and TcBS, respectively, with an area under the curve of 0.813 for TcBF and 0.815 for TcBS (p < 0.001). Conclusions: Measurement of transcutaneous bilirubin is a fast and painless method that can be considered a reliable tool for screening and monitoring neonatal jaundice, but not for a definitive diagnosis to decide the use of phototherapy in full-term newborns at 3400 m above sea level.