In this paper a simulation analysis of an automated single-tray Vertical Lift Module (VLM) system is presented. Compared to other well-known warehouse systems, a VLM system can provide moderate throughput capacity and lower investment cost. The objective of the study is to investigate benefits of a single-tray VLM system design in terms of reducing transactions' mean cycle time, which results in increased throughput of the system. Performance of the single-tray VLM is evaluated regarding alternative design configurations and the velocity profiles.The results show that single-tray VLM systems are effective and may serve as guideline for warehouse designers in designing a new or improving an existing automated warehouse system.