LabFlow is a workflow management system designed for large scale biology research laborato-ries. It provides a workflow model in which objects flow from task to task un-der programmatic control. The model supports parallelism, meaning that an object can flow down several paths simul-taneously, and sub-workflows which can be invoked sub-routine-style from a task. The system allocates tasks to Unix processes to achieve requisite levels of multi-processing. The system uses the LabBase data management system to store workflow-state and labo-ratory results. Lab-Flow provides a Perl5 object-oriented framework for defining workflows, and an engine for executing these. The software is freely available.