Our aim is to demonstrate a sensitive homogeneous chemiluminescence immunoassay (CLIA) for Methotrexate using the priciple of chemiluminescence energy transfer. This will lead to a technique for the detection of anti-neoplastic drugs that requires high sensitivity, by a method that is simpler, faster, safer and cheaper than conventional methods. Methotrexate will be covalently coupled to aminobutylethyl isoluminol (ABEI) without loss of immunological or chemiluminesence activity. It will then be used in conjuction with fluorescent labeled antibodies and the principle of energy transfer to develop sensitive homogeneous (non-separation) assays for methotrexate. After optimisation, this assay will be compared with a commercial assay. The research is expected to provide a homogeneous methotrexate assay with lower detection limits, using stable reagents. The assay will be safer, simpler, easily automated and cheaper than commercial assays. The removal of the separation step will also lead to increased precision and accuracy. The work will lead to a phase II prototype instrument design and development production of antibodies and clinical trials for assays, for methotrexate and other anti-neoplastic and therapeutic drugs.