A descriptive cross-sectional study was conducted to find out the disease pattern and health seeking behaviour of slum dwellers in some selected slums of Dhaka City. Out of 1029 respondents, 536 (52.1%) were male and 493(47.9%) were female. The mean age of the respondents was 19.50 years (SD ± 17.929). Most 704 (68.41%) of the respondents were employed like domestic work, day labour, rickshaw puller, small business, transport work or helper and butcher. Regarding educational status, 589 (57.3%) were illiterate and 440(42.7%) were literate. The mean family income of the respondents was Tk 7202.43; (SD ± 2969.902). During the preceding 21 days, 511(49.65%) slum dwellers were sick and 518 (50.34%) were not sick at that period. The male slum dwellers 153 (14.9%) were mostly affected by diseases of the respiratory system (Cold /cough /fever /asthma /tonsillitis /pharyngitis) and the female slum dwellers 122 (11.9%) were mostly affected by diseases of the digestive system (Gastric /diarrhoea /fever/ hepatitis/ helminthiasis). Most 921 (89.4%) of the slum dwellers sought health care services during sickness. Majority 476 (46.3%) of the slum dwellers consulted drug sellers of pharmacy during illness. Among rest, 238 (23.1 %) slum dwellers preferred going to the medical college hospital, 162 (15.7 %) respondents preferred going to government hospital and 124 respondents (12.1%) consulted a private practitioner. According to the reasons for not seeking treatment, majority (26%) of the respondents did not seek treatment due to lack of money and 25% respondents were waited for self-recovery. Rest of slum dwellers did not seek treatment due to the distance; services were unknown and waited for self-recovery and lack of money. Only 22% respondents gave multiple answers. Highly significant association was found between the education and monthly family income of the slum dwellers with health seeking behaviour during illness (p=0.002 and p=0.01).