Nutritional deficiencies are important and widespread problems in most developing countries. Preventing and correcting micronutrient deficiencies are important because of the multiple negative consequences of these deficiencies. This study was designed to determine the prevalence of copper deficiency in an adult population in Shiraz, southern Iran. We also determined the association between copper status and other factors such as age, sex, and body mass index (BMI). In this cross-sectional study, 416 adults residing in Shiraz were selected by two-stage sampling. Serum copper was measured by flame-atomic absorption spectrometry. The data were analyzed with SPSS software. Mean age in our sample was 39.33 ± 15.06 years, and mean BMI was 26.17 ± 4.81 kg/m(2). Mean serum copper concentration was 118.15 ± 54.33 μg/dL in the whole sample, 109.74 ± 56.22 μg/dL in men, and 122.15 ± 53.04 μg/dL in women. The overall prevalence of copper deficiency was 24%. The prevalence of copper deficiency differed significantly between men and women but not between different age groups. Serum copper concentration correlated significantly with BMI (p < 0.05). This study is the first to evaluate serum copper status in a healthy population in southern Iran. We show that the mean copper concentrations were higher than those reported for Iranian populations in northern cities and were also higher compared with studies in most other countries. We suggested more detailed studies to identify the etiological determinants of this nutritional deficiency in Iran and elsewhere.