This cross sectional study describes the knowledge, attitude and practice (KAP) among 100 patients attending the diabetic clinic at Klinik Kesihatan Seri Manjung from December 2002 until January 2003. A face-to-face interview using a structured questionnaire was carried out for data collection. The results revealed that 87% of the respondents were able to answer 50% or more questions on knowledge correclty, while 98% of them had 50% or more score for the attitude questions. Ninety-nine percent of them reported 50% or more score for the questions on practice. However, only 56% of them practice all 4 of the practices that were asked - regular exercise, healthy diet, monitoring blood glucose level, and monitoring body weight. There was a significant positive correlation between knowledge and attitude (r=0.536, p<0.01), but there was no significant correlation found between attitude and practice. The results indicate that an increase in knowledge will increase the attitude, however this is not necessarily the same between attitude and practice. A better structured educational programme on diabetes and preventive measures should be conducted for all especially those with diabetes to improve their practice towards diabetes. Keywords: Diabetes Mellitus, Knowledge, Attitude and Practice (KAP)