This study aimed to provide the prevalence of vitamin/calcium supplement use and, to explore the gender differences in and the correlates of supplement use. Data came from the 1994 National Health Interview Survey of 3,814 households; and 7,019 respondents (3,561 females and 3,458 males) aged 25 years old and older were included in the analysis. Supplement users were defined as individuals who reported taking any supplements at least once a week. Associations between supplement use and its correlates were examined by using chi-square analysis and logistic regression. The results indicated that 22.2% of females and 12.7% of males used vitamin supplement, and 10.2% of females and 3.7% of males took calcium supplement. The adjusted sex odds ratio was 2.8 (95% CI = 2.4-3.2) for vitamin supplement use and 3.8 (95% CI = 3.0-4.7) for calcium supplement use when sociodemographic and health variables were controlled. Increased likelihood on the use of vitamin/calcium supplement was associated with sociodemographic characteristics (females, over 45 years old, more educated) and health behaviors (more regular exercise and check on blood pressure). Additionally, females who received regular Pap smear or with no chronic disease tended to take more vitamin supplement and females who perceived themselves with a poor health condition were more likely to use calcium supplement than others.