Background of this study is the phenomenon of investigative reporting practice in relation to the journalist's professionalism. This research method is the case study. This research focuses oninvestigative reporting practice in Tempo magazine; journalist's professionalism in investigating in perspective of competency standards of reporter; and interplay between structure and agency. The conclusion is journalist have competency to conduct investigative reporting on the basis of good experience. In the implementation of journalist-competency standard, detail process of investigation can not be conducted according to working procedure. The fact shows that investigative reporting ofTempo is earlier in situation anticipation. In the process of investigative reporting,the role of structure and agency gives freedom to each other for journalists. Investigation team's rule of Tempo enables and constrains according to rule and resources. But, Tempo investigative reporting team has its own standards. In certain cases of investigative reporting, Tempo reporters implement higher level of competency than journalist-competency standard. Related to Structuration theory between structure and agency structure in reality, structure do not overburden team performance.The structure does not hold a decisive role. Interplay does not depend on structure. Other researchers should conduct observation research in media which apply competency test for reporters from other agencies.