Recent advances in genome technology have enabled genome-wide searching for disease predisposition loci, using dense SNP and haplotype maps. Over the past year, such approaches have yielded positive results in human hypertension. Here we outline factors underlying the rationale for the approach and consider reasons for false positive and negative results. Although the approach has yielded positive results, typically the trait-associated loci explain only a small fraction of the heritable fraction of trait variance. Finally, we consider alternative approaches and emerging strategies to probe the role of heredity in control of blood pressure.