The Buddha Himself first laid down the rules of monastic discipline governing the Order. They were then recorded in the books of disciplinary rules called the Vinaya. A disciplinary code called the Patimokkha was also compiled in order to regulate the day-to-day conduct of the members of the Order. This code listed various offences and their penalties. The members of the Order recite it today during their assemblies on the new moon and full moon days of each month. This regular recitation of the code is to remind them of the rules of discipline and to give each one an opportunity to openly declare his breaking of any rule.

There are more than two hundred and twenty-seven rules governing the conduct of members of the Order. The first four rules are the most important and they concern the refraining from:

(1) sexual intercourse;
(2) theft;
(3) taking of a human life;
(4) false proclamation of miraculous powers.

Breaking any one of these rules will result in expulsion from the Order.

Some of the other rules concern the social conduct of the members of the Order, both within the monastic community and towards the lay community. Rules concerning the acquisition and use of basic necessities such as dwelling places, food, clothing and medicine are also included. These rules help members of the Order to avoid harming others, to practise moderation and purify their minds, thus creating conditions favourable for the practice of the Teaching. For the members of the Order, moderation in eating, living in a secluded dwelling and the practice of meditation are the most important.