Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death in the United States today and is projected to rise to second in the next 5 years. The low survival rate in PDAC cases is partially attributed to the ability of this cancer type to rapidly metastasize. However, little is known about the molecular events that occur during metastasis, which precludes identification of viable drug targets for this process. To address this shortcoming, we have developed a novel multiplexed in vivo screening platform to identify chemical inhibitors of metastatic seeding. This assay utilizes murine and human genetically barcoded PDAC cell lines and Illumina sequencing to determine the effects of test compounds on the ability of these cells to seed the lungs of recipient mice. While most in vivo screening is hindered by very low throughput, the multiplexed nature of this strategy allows us to screen a full 96-well plate in one mouse. Using a unique library of serine and cysteine hydrolase-directed small molecules we have identified a compound that selectively inhibits metastatic seeding in vivo, while displaying low cytotoxicity. Activity-based protein profiling (ABPP) using MudPIT mass spectrometry identified the serine hydrolase ABHD6 as the target of this compound, which was validated using in-gel fluorescence competition experiments. The role of ABHD6 as a critical regulator of metastatic seeding in vivo was determined using intravenous injection of stable shRNA knockdown cell lines in a mouse model as well as pretreatment with selective ABHD6 inhibitors. Current work is focused on deciphering the molecular effects of ABHD6 inhibition using lipidomics and assessing the efficacy of long-term compound treatment in preventing metastasis in a subcutaneous transplantation model. These results are significant in understanding the underlying molecular mechanisms of PDAC metastasis and identifying potential drug targets in treating this disease.