This guide covers laboratory characterization procedures for identifying bacteriophage lambda or its DNA and assumes that the reader has basic knowledge in virology and molecular biology. Bacteriohage lambda is a temperate bacteriophage with an icosahedral hear and a single, non-contractile tail ending in a single tail fiber. The lambda genome consists of a single molecule of linear double-stranded DNA and has cohesive ends. The naturally preferred hosts is Escherichia coli K12. Hundreds of lambda variants derived from wild type lambda can be used in biotechnology and differ in genome size and genotype. These are used primarily as DNA vectors for cloning DNA fragments. Judging uncontaminated, pure lambda should be done through restriction enzyme analysis DNA characterization and the presence and identification of lambda DNA is accomplished by polymerase chain reaction. The primers used for detection of bacteriophage lambda should be chosen based on the reason for detection.