England, used all its means to occupy the southern lands of the Ottoman Empire during the First World War. In this context, one of the tools he used was his agents, who took an active role in the field as trained manpower. John Philby, who was one of the agents mentioned served in different locations during the war years. The appointment of Najd, which took place in November 1917, was a turning point in his life. The reason for the trip was the incitement of Ibn Saud against the Amir of Hail, Ibn Rashid, and the Ajman tribe. It was to ensure that he acted together with Hussein, who rebelled against the Ottoman Empire by collaborating with the British. Although his success is debatable, he had the opportunity to get to know the inhabitants, settlements, geography and climate of Arabia during his travels. With the observations he made and the experiences he gained, he produced valuable works that will enable the lands of Arabia to be better understood. Philby was faced with Ibn Saud's demands for Arab captives who were captured by the British while fighting within the Ottoman Empire. In our study, in which the expectations of the parties from each other are reflected, it is aimed to give information about the Nejd mission that enabled Philby to meet Ibn Saud and his achievements within the scope of the mission. Because the friendship of Ibn Saud-Philby, whose foundations will be laid with this mission, enabled the Wahhabi Amir to be one of the closest people to Philby during and after the construction of his state.