Retailers increasingly seek to provide omnichannel fulfillment as a way to improve customer experience. However, many find themselves challenged by the complexity these efforts pose for underlying logistics support systems. This report identifies the major logistical issues related to omnichannel fulfillment with a focus on network planning, transportation, inventory, and reserve logistics, and it provides direction to supply chain management pros and their application development and delivery (AD&D) counterparts on how to address them.