This thesis is of three main objectives:- 1) to study Kalyānạmitta in Theravāda Buddhism, 2) to study the role and the importance of Kalyānạmitta  in Theravāda Buddhism,  3) to study the importances of Kalyānạmitta  influential to the Thai Buddhists. This research is a qualitative one by studying from the Buddhist scriptures:- the Tipitaka, the books, the academic papers and  the  related researches.

From  the study,  it is  found that  the Kalyānạmitta  which the Buddha  said mean a virtue of a good friend to persuade or advise the friend in a good thing. the Kalyānạmitta  is beneficial to others and a good friend in the good environment in residential land, trees, etc.  Kalyānạmittas  fulfill the Samanadhamma.

From  the characteristics  of Kalyānạmitta, it is found that they are the characteristics possessed by the people who have  moral qualities, namely Saddhä, Sila, Suta, Cāga and Paññā. The mentioned characteristics are the worldly ones which are of the virtues to be the refuges to other people and to be helpful to others. On the contrary, the Kalyānạmitta  of Lokuttara Level is of the high level which consists of the Buddha and Phra Arahantas who are to lead the human beings to Ariyamagga and to be away from suffering and finally to attain Nibb±na.

From the  analysis  of  Kalyānạmitta  in  Thai  Buddhist  disciples, it is found  that  there  are many techniques  in  both  of  the  good  teaching  and  good  practice, that can  tell,  advice, and show  the  way  of  the  development  both  bodily  and  mentally  for  Buddhist  disciples  living in the  middle  way,  the  Noble  Eight  Fold  Path  and  the  Four  Noble  Truth  which  is to get  rid of suffering.  

From  the value of  Kalyānạmitta  in Tipitaka,  it is  found that it is the way of carrying out the life in 3 ways, namely: Kāyasucarita, Vac²sucarita and Manōsucarita.  These values can develop the human lives to be of qualities and to reach the Four Noble Truths which are the ways to go away from suffering.

The problems in Thai societies are the economic problem, the moral problem and the ruine problem, the sexsual trading problem, the narcotic problem, the quarrel problem, the criminal problem etc;  all of which arise for lack  Kalyānạmitta.