Although a variety of injectable agents are available for soft tissue augmentation, no perfect filler material exists. The advantages and disadvantages of commonly used materials such as bovine collagen have been well documented. However, many newer injectables are still undergoing experimentation to determine their clinical efficacy and long-term safety. This article details recent scientific work to compare injectable materials from the following categories: xenografts (bovine collagen and hyaluronic acid derivatives), autografts (autologous fat, Isolagen, and Autologen), homografts (Dermalogen and Cymetra), and synthetic materials (fluid silicone and Artecoll).