Tooth wear is the loss of tooth tissue and structures not due to caries. It can occur in various forms either attrition, abrasion, erosion, noncaries cervical lesion (NCCL) or a combination of two or more forms. The objective of this study was to determine the patterns and associated aetiologies of tooth wear among adults in Kelantan, Malaysia. This crosssectional study involved 81 adults with tooth wear which was visually assessed using the Smith and Knight Tooth Wear Index (TWI). A questionnaire was used to seek putative aetiologies of the wear. Data were analyzed and the results were expressed as frequencies and percentages. Six thousand three hundred and eighty four tooth surfaces were examined in 1596 teeth. 17.4% surfaces had tooth wear; 80% scored 1, 18% scored 2 and 2% scored 3. Among the 81 cases of tooth wear, 29 (35.8%) had abrasion; 25 (30.9%) had attrition; 1(1.2%) had erosion while 26 (32.1%) had the combined type. Among those with abrasion, majority had the habit of eating freshwater clams (Corbicula fluminea) as local delicacy where most of the times people use their teeth to pry open the clam shells. Erosion was related to the pooling of carbonated drinks or beverages in the mouth before swallowing. In conclusion, most adults experienced abrasion and the most common possible associated aetiology is the way of eating clams.