LabFlowis a workflowmanagementsystem designed for large scale biologyresearch laboratories. It providesa workflowmodelin whichobjects flowfromtask to task under programmaticcontrol. Themodelsupportsparallelism, meaningthat an object can flowdownseveral paths simultaneously, and sub-workflowswhichcan be invokedsubroutine-style froma task. Thesystemallocates tasks to Unix processes to achieve requisite levels of multiprocessing. Thesystemuses the LabBasedata management systemto store workflow-stateandlaboratoryresults. LabFlowprovides a Perl5 object-oriented frameworkfor defining workflows,and an enginefor executingthese. The softwareis freely available.