Anti-tetrahydrocannabinol (THC), anti-cocaine and anti-morphine polyclonal antibodies were produced. These antibodies were successfully applied to an ELISA format for the detection of THC, cocaine, and morphine in saliva samples. Monoclonal antibodies against amphetamine and its derivatives were produced using two different conjugates, amphetamine-bovine serum albumin and methamphetaminebovine serum albumin. Two successful clones were produced, and the antibodies were applied to an ELISA format for the detection of amphetamine, methamphetamine, and the other common amphetamine derivatives, such as methylenedioxyamphetamine (MDA) and methylenedioxymethamphetamine (MDMA). The ELISA was developed using saliva as the matrix. During the screening stage of the production of these antibodies, particular attention was given to their cross reactivity profiles. Among the molecules tested for cross-reactivity, were legally available medications such as ephedrine, as other commercially available antibodies show cross reactivity. The resulting monoclonal antibodies detected amphetamine and other designer derivatives, and showed negligible cross reactivity with the legal structurally related molecules. The antibodies were applied to a biosensor (BIAcore) assay for the detection of amphetamine and methamphetamine in saliva samples. The affinity constants for the antibodies were determined by ELISA and BIAcore methods. The values obtained were found to be similar by both methods. A novel automated prototype device, developed by our collaborators, Envitec, was optimised and the anti-THC polyclonal antibody was applied to it for the screening of saliva samples for the presence of THC. This was a rapid, qualitative test, and it could be performed in less than 20 minutes. The basis of the assay was competition between horseradish peroxidase-labeled THC and THC present in the saliva samples, for binding to the anti-THC polyclonal antibodies that coated the reaction wells of the device.