Objective: To determine the frequency of vitamin D deficiency and insufficiency in a low-income peri-urban population.Methods: The cross-sectional study was conducted in a low-income, unplanned settlement in Karachi, and comprised apparently healthy adults who were recruited randomly with informed consent. Serum levels of 25-hydroxy vitamin D were measured using a kit obtained from Roche Diagnostics. One-way analysis of variance and logistic regression were used for statistical analysis.Results: Of the 858 subjects, 507(59%) were females and 351(41%) males (age range: 18-60 years). Prevalence estimates of vitamin D deficiency (\u3c20ng/ml) and insufficiency (20.0-29.9ng/ml) were found to be 501(58.4%) and 269(31.4%), respectively. Odds ratio of vitamin D deficiency was significantly higher in females compared to males after adjusting for education and smoking status (p=0.001).CONCLUSIONS: High prevalence of vitamin D deficiency among females in one of the peri-urban areas points towards a public health problem which requires attention of the medical community