This invention provides a high throughput survival assay, using uptake of a marker dye (e.g. a fluorescent dye) as a marker of death of a nematode. The assay permits high throughput screening of thousands of compounds possible. By the application of automated worm handling technology we are able to accurately dispense nematodes into 384 well microtitre plates, at rates many thousand of Limes faster than previously possible. In addition, we have automated the analysis of survival by the use of a fluorometric plate reader that quantitates the degree of fluorescence within each well.