Bahâ Saîd Bey (1882-1939) is one of our national heroes during the transition period from the Ottoman to the Republic and dedicated his existence to his country and nation with his distinguished personality. He was appointed by the administration of the period to closely examine the Alevi-Bektashi communities, Tahtaci, Chetmi and Hardal Turkmens in Anatolia in terms of their ancesters, languages, sects and traditions. Having an intellectual personality, Bahâ Saîd’s researches on Alevism Bektashism were published in newspapers and magazines such as Muhibbân, Memleket and Meslek, especially in the Türk Yurdu journal. His articles published in the Türk Yurdu journal are consist of field researches made by scientific methods and they supply detailed information. Bahâ Saîd’s field researches cover a long period. Therefore, the information given at the end of the researches is very important. His researches on the Alevi-Bektashi and Nusayriya have a special importance as they are the firsts in Turkey. In this study, it was aimed to determine Bahâ Saîd’s researches on Alevi Bektashi and Nusayriya communities and his thoughts on these communities. Bahâ Saîd gave general information about the origins and rites of the AleviBektashi belief in his field researches. In addition, in this study, it was observed that Bahâ Saîd, who applied participatory observation and interview techniques, examined the belief and cultural systems of other communities in Anatolia, especially Alevis and Bektashis, and determined the presence of traces of ancient Turkish culture in them.