This article discusses a mamacan tradition in Bayan village North Lombok West Nusa Tenggara. This tradition has been practiced since many years ago by a local community called adat Bayan. This adat community is the descendants of former Kedatuan Bayan, a small kingdom that existed around the 16 th century. Data of this study are gathered through three methods, namely interviews, observation, and documentary research. The findings of this study show that mamacan is a tradition of reading manuscripts (lontar/takepan) done by a pambacan (a reader). Then the translator will translate and explain the meaning of the lontar. This tradition is usually conducted during certain rituals and events, such as wedding ceremony, circumcision ceremony, cutting baby's hair, and other rituals. The manuscript for mamacan is selected based on the ceremony type since different rituals will use different manuscripts. For instance, manuscript entitled Jatiswara, Nursada, Nurcahya, Bang Bari, and Nabi Haparas. These manuscripts contain various local values and religious teaching; therefore, mamacan is one of the ways to preserve tradition and disseminate religious values. However, not all people can read that lontar and understand its meaning. Most of those manuscripts were written in Jejawan (Old Javanese letters) and Sasak and Javanese letters, and a combination of Javanese Sasak languages.