This study documents the prevalence of Hepatitis B serological markers among STD patients who have had multiple sexual partners in Kuala Lumpur, Malaysia, and compares the rates with those of a sample of the population with single or no sexual partners. A total of 336 Chinese STD patients (multiple partners group) and 234 Chinese control subjects (non-multiple partner group) were screened. Those with a history of blood transfusion or parenteral drug abuse had been excluded from the study, and all study subjects were heterosexuals. The overall carrier rate was 9.2% for the multiple partner group (MP group) and 6.8% for the non-multiple partner group (NMP group). Infection rates were 64.3% for the MP-group and 38.9% for the NMP group. After adjustments for age and sex, there was no significant difference in carrier rates between the two groups, but infection rates were significantly different with the MP group, being 3.2 times more likely to acquire infection than the NMP group. The study concludes that in heterosexuals, those with multiple sexual partners have increased chances of acquiring HBV infection.