The objectives of this thesis are to critically examine the concept of Upadana found in Theravada Buddhism and its impact on modern Thai society.  The main focus of the study would be centred on the meaning category and the relationship between Upadana and other related concepts in Buddhism,  its penalty and impact on Buddhist society, and the ways to learn or understand Upadana for eradicate  them. 

                        The result of the study found that Upadana in Theravada Buddhism means clinging  or attachment.  Upadana in Theravada Buddhism has four types: 1. Kamupadana (clinging to sensuality) 2. Ditthupadana (clinging to views) 3. Silabbatupadana (clinging to mere rule and ritual) 4. Attavadupadana (clinging to the ego-belief). In accordance to the relationship with other principle in Buddhism, Upadana can be seen in the following ways:

                        In the docrine of causes and conditions (Paticcasmuppada), Upadana comes into existence depending on various causes and conditions.

                        According to the principle of three charecteristics (Tilakkhana), Upadana is subject to impermanence, suffering and selflessness, which are common to all beings.

                        For the four Noble truth (Ariyasacca), Upadana can be seen as the cause of suffering and it is one of defilements.

And, in the Five Aggregates (Panca-khandha), Five Aggregates  are the clinging  objects of Upadana which  all human beings misunderstand in permanence of beings.      

                        According to Buddhist scholars’ views, Upadana causes penalty and suffering  in the present and in the future.  It affects Buddhist society in several ways:  such as  impacts on belief, education, economy and politics, ways of lives and ecology.