The purpose of this study was to determine whether earthworm coelomocytes are capable of performing chemotaxis in response to selected pathogen-associated molecular patterns (PAMPs). The ability of cells to exhibit chemotaxis in response to different chemical mediators is of key importance in normal cellular processes. The invertebrate model used for this study was the earthworm Eisenia hortensis, and the PAMPs included lipopolysaccharide, lipoteichoic acid, flagellin, and laminarin. Determination of migratory capacity in annelids will provide insight into the evolution and conservation of chemotactic pathways in invertebrates. In this study, a combined Boyden-flow cytometric technique was used to measure chemotaxis of earthworm coelomocytes (leukocytes). Coelomocytes were placed in the upper chamber of the migration plate and the PAMPs were placed in the lower chamber at varying concentrations to investigate dose response effects. Post-incubation, the coelomocytes that had migrated across the membrane were harvested and enumerated using a flow cytometer. Statistical analysis showed consistency and reproducibility of chemotaxis to all of the PAMPs that were tested in this study. The results show that earthworm coelomocytes exhibit chemotactic responses to molecular patterns common to microbes that inhabit their natural environment. We conclude more research is needed at the molecular level to elucidate the signaling pathways involved in the migratory responses observed, which is of key importance in understanding the degree of conservation of chemotactic pathways amongst invertebrates.