This research work aims at the study of the biographies and the main duties of the two experts in monastic disciplinary codes from the evidences in the three Buddhist Canons (The Tipitake) : a study of Bhikkhu Upālî Thera’s Case, and Bhikkhunî Patācārā Therî’s by emphasizing their eminent roles, especially in the light of learning and teaching the disciplines, supporting the monastic assembly as well as their duties in the propagation of the Buddha’s teaching as striking prototypes setting the law suit which the new generation should imitate.

            The main topics for study are divided into five chapters as follows :

Chapter I : The importance of problems and objectives of study.

Chapter II : The roles played by the experts in Vinaya codes and the importance of the Buddhist monastic disciplines.

Chapter III : The biographies of both bhikkhu and bhikkhunî, expert in the Buddhist Monastic Codes, and Their relationships with many people.

Chapter IV : The roles played by monks expert in Vinaya Codes in Further studies and the judgment of law suits, and the roles in teaching played by the Bhikkhunîs expert in Vinaya codes.

            Chapter V : Conclusion and suggestion.

            From the study of the roles played by the monks expert in Vinaya Codes (Vinayadharas) in the Buddhist Disciplinary Cannon (Vinaya-Pitaka) both in Bhikkhu Upālîî Thera’s case and Bhikkhunî Patācārā Therî’s their particularly eminent roles can be mentioned as follows :

            Among The Buddhist monks expert in the Vinaya Codes. Upālî Thera was surely the greatest one who had higher aspiration in the study of the Buddhist monastic codes having been heaping up the will or attention to be an expert in disciplinary codes from the previous life. Depending upon the experience and skill continuously accumulated step by step, he became an eminent expert in the Buddhist disciplinary codes and took responsibility in teaching Vinaya or disciplines to the monks’ assemblies. Besides, he contemplatively and profoundly tried to find out the knowledge of the Buddhist monastic codes in all respects. Whenever there had been a serious problem with reference to the Buddhist monastic codes he approached the Buddha and asked Him about the problems in Vinaya, such as the judgment of law suits and the punishment to the wrong doing monks.

            The Buddha had Confidence in him and always assigned him to consider and judge the important cases many times. Take for example the Bhikkhuni, the Kumarakassapa’s mother’s case. The pregnant Bhikkhuni came to be ordained in Buddhism without knowing that she was already pregnant. Bhikkhu Upali was given authority by the Enlightened One to judge this case in the midst of the four Buddhist assemblies and in front of king Pasenadikosala.

            Patacara, Theri an expert in the Buddhist Vinaya Codes who had been desirous of studying Vinaya from the past life, set up her will or attention to be specialized in Vinaya. She seriously took responsibility in teaching Vinaya to the assembly of the Bhikkhunis She was Pavattini (female preceptor) in the assembly of the Bhikkhunis She did good treatment to the assembly of the Bhikkhunis by instructing them in Buddhism. Her aphorism can be found in the scripture of Therigatha.

            The eminently special roles and the ways of life found in both Bhikkhu Upali Thera, and Bhikkhuni Patacara Theri, regarding the upholding of the Buddhist monastic codes have been the means which the male and female disciples have followed up to the present time.