An outbreak of dengue and dengue haemorrhagic fever was studied in Bandar Baru Bangi, Hulu Langat District which started from epidemiological week 51 of December 2001 until ]anuary 2002. Altogether, 53 cases were reported to the Hulu Langat District Health Office with 24 cases detected in Section I and Section 6, and 5 cases in Section 4 of Bandar Baru Bangi respectively. Two cases were confirmed as dengue haernorrhagic fever (DHF). The majority of the cases were female Malays. The age of the cases ranged from 3 to 60 years with a mean of 29.17 : 13.18 years old. The majority of patients were mainly private sector workers from factories or companies with 29 cases (54.7%) and university students with 14 cases (26.4%). No deaths were reported in this outbreak. On the average, the duration taken for a patient to be admitted from the date of onset was about 4.4 - 2.0 days and the duration taken for notification from the date of admission was about 2.0 - 1.7 days. The majority of cases reported were based on classical clinical features of dengue fever. Only 18 cases (34%) were IgM positive for dengue. The statistical analysis showed that the majority were male (P>0.05), Malays (P>0.05) , age group of 21»30 years (P>0.05), platelets level < 100,000 per mm3 (p>0.05) and the serological specimens obtained 5 days after the date of onset (p2.0%) within residential premises in this locality with 46 Aedes mosquito breeding places identified and a total amount of RM 6500 of fines imposed.