The amplified (restriction) fragment length polymorphism (AFLP) technique is a method for DNA profiling that is now widely applied for assessing diversity among various organisms with varying genomic complexity, from small bacterial to large plant genomes. AFLP analysis combines the reliability of restriction enzyme digestion with the utility of the polymerase chain reaction. The technique can be applied to studies of DNA of any origin and complexity, without prior sequence knowledge. Therefore, it is very versatile and particularly valuable for organisms for which no substantive DNA sequence data are available. AFLP detects the presence of point mutations, insertions, deletions, and other genetic rearrangements. Typically, the fragments detected by AFLP are inherited in Mendelian fashion as co-dominant markers, making the technique amenable to tracking inheritance of genetic loci in progeny from crossed lines of organisms, and in studies of population genetics. This chapter describes the principles of AFLP and experimental procedures.