The Johns Hopkins Bloomberg School of Public Health Department of Epidemiology has the oldest formal academic program in genetic epidemiology, initiated by Dr. Bernice H. Cohen in 1979. Genetic epidemiology focuses on methods to identify genetic factors contributing to complex diseases, where both genes and environmental risk factors are important in the etiology. Technologic developments in the past decade have transformed the field of genetic epidemiology, and now most research must deal with very large genomic data sets, including genome wide marker panels, large microarray sets of expression data or massive sets of sequence data. While high-throughput genomic technologies have created new opportunities for understanding how genes and their regulatory factors control disease risk, they also force us to reconsider data collection, cleaning, management and analysis. The genetic epidemiology program aims to train Masters, Doctoral and Post-Doctoral scientists in study design, statistical approaches and methodology appropriate for analysis of complex diseases with substantive academic training in a core sequence of courses in Epidemiology, Biostatistics and Genetic Epidemiology.