The Malaysian Dietary Guidelines (MDG) with eight key messages were first published in 1999. An updated version consisting of 14 key messages is being developed. The objective of this study was to evaluate the understanding of five key messages of the updated MDG among adults aged 18-59 years in Kuala Lumpur. A total of 773 adults comprising 330 Malays, 364 Chinese and 79 Indians were included in the study. A self-administrated questionnaire was used to obtain demographic data and to determine the level of understanding of key words and messages to be included in the new MDG. The results showed that 63% of the subjects were not aware of the existence of the MDG published in 1999. Overall, the understanding of the five messages in the updated MDG was moderate with a mean score of 60.0 ± 16.5. Between 52% to 93% of the subjects did not understand such key words as serving size, sedentary habits, blended vegetable oil and shortenings. The mean scores of understanding were significantly higher (p< 0.05) among the Chinese subjects (61.3 + 17.8) than Malays (58.6 + 14.2) and Indians (60.0 + 18.9). The younger subjects (61.2 + 16.0) scored significantly (p< 0.05) higher than the older (58.7 + 17.0) counterparts. There was also a significant association between the level of understanding of MDG with education level (p<0.001) and occupational status (p<0.001), respectively. This study suggests that some key words and messages in the updated MDG should be simplified to ensure that they are understood by Malaysians.