Recent revolutionary progress in human genomics is reshaping our approach to therapy and diagnosis. Nucleic acid– based testing is becoming a crucial diagnostic tool not only in the setting of inherited genetic disease but in a wide variety of neoplastic and infectious processes. Molecular Diagnostics is a collection of techniques used to analyse biological markers in the genome and proteome—the individual's genetic code and how their cells express their genes as proteins. Molecular Diagnostic tests detect specific sequences in DNA or RNA that may or may not be associated with disease, including single nucleotide polymorphism (SNP), deletions, rearrangements, insertions and others as shown through karyotyping. Following diagnosis, molecular diagnostics provides the necessary underpinnings for any successful application of pharmacogenomics or biologic response modifiers as well as assessing disease prognosis and detecting minimal residual diseases. The earliest understanding of molecular diagnosis could be exemplified by the detection of amino acid substitution in the Sickle cell gene. The methods used include Polymerase Chain Reaction and real time PCR, spectral karyotyping and DNA microarrays. PCR is based on utilizing a pair of priming complementary sequences (oligonucleotide primers) flanking a location of interest, together with unique heat-resistant polymerases (DNA copying enzymes), to produce multiple copies of a targeted chimeric gene. This course is therefore designed for laboratorians to expose the basics of molecular diagnosis as well as the unending evolution of technologies available in disease diagnosis and its applications in pharmacogenomics. It is hoped to enhance our individual knowledge expository and the possibilities of applications of modern diagnostic methods as compared to standard chemical, biochemical, haematological and microbiological laboratory testing methods.