Cathodic protection is one of the most widely used applications for protecting underground and submarine metallic structures from corrosion. This method is based on providing the electrons, which metallic structures lose as a result of electrolytic reaction, by the cathodic protection system. However, from time to time, it may be possible that there is some unwanted interference input into the metallic structure in such applications. This study is aimed at ascertaining the existence, arising frequency, and magnitude of an interference called the telluric effect that is going in and out of the natural gas pipeline between Duzce and Karadeniz Eregli in Turkey, which is 60 km in length and has a 40.64 cm diameter, and is well coated with polyethylene. In this study, the pipe/ground potential values, electrical currents coming from the anode bed, and soil resistivity values were measured at different times and regions along the pipeline. In conclusion, it was found that these changes did not arise at a certain period or at any point between the Duzce PIG and Eregli RMS station, although it did occur strongly around the Akal Take-Off.