The laboratory medicine is advancing towards the use of molecular techniques and molecular diagnostics for the detection of leukemia, genetic disorders, preimplantation screenings, pharmacogenomics, infectious diseases, and cancers. Molecular diagnostics dates back to 1980s but now has grown exponentially. The field has a wide range of applications including identifying individuals at risk of developing certain disorders (either genetic or nongenetic), screening of apparently healthy populations, determining prognosis, diagnosis, and monitoring patient's response to therapy. Molecular diagnosis is a very helpful tool that helps to provide very fast and accurate information about the heritable defects. This in turn helps the physicians to provide carrier analysis, prenatal counseling to the family members at risk. Personalized medicine allows an individual to have a panel of genetic tests performed to determine predisposition to disease. Molecular diagnostics can also aid in making decision about therapy to be used for genetic disorders. In this special issue, we try to bring the new and existing molecular diagnostics techniques available for the diagnosis of heritable, cancerous, and infectious conditions. The papers in the special issue have shown the use of new techniques that can help the laboratory to better serve the patient population in the coming years. This special issue has six articles, where one review article discussed use of proteomics approach for molecular diagnosis of the cancer, followed by an article focusing on cancer diagnosis. These articles describe recent advancement in the field as well as useful tools in the assessment of cancer. One of the papers has efficiently used the fluorescence in situ hybridization (FISH), quantitative reverse transcriptase PCR (qRT-PCR) to track the fusion gene in prostate cancer. K. Tuononen et al. have compared four different methods to identify the anaplastic lymphoma kinase (ALK) gene rearrangements that occur in a subgroup of non-small cell lung carcinomas (NSCLC). Q. Zou et al. have shown the use of biomarker to monitor progression and prognosis of gallbladder cancer. Furthermore, in this issue G. S. Pandey et al. have described a flow cytometry-based detection of intracellular factor VIII which plays important role in very common genetic disorder, hemophilia A. On the same line a PCR-based approach has been described to identify and monitor the pathogens during the outbreak of infections. D. Paul et al. have reviewed and discussed tissue culture-based discovery of potential biomarkers using various mass spectrometry-based proteomic approaches. K. Tuononen et al. screened ALK gene fusions in lung …