Two general approaches toward the identification of new genes which may contribute to specific developmental, physiologic, or pathologic processes can be pursued: (1) a strategy of positional cloning or reverse genetics and linkage analysis in which affected individuals or families are studied to identify defective genes, and (2) an immediately focused approach which uses available partial information about a gene to screen cDNA libraries toward the isolation and characterization of the complete gene. The general principles that form the basis of how these two strategies aid the gene hunter in the pursuit of new genes is discussed. The modern day urologist should become familiar with these techniques and the promise they hold for the future diagnosis and treatment of urologic diseases.