The recent innovations and advancements in the safety and efficacy of facial fillers have made them one of the most popular modalities in facial aesthetics. The most popular filler products for the face include hyaluronic acid (HA), calcium hydroxylapatite (CaHA), poly-L-lactic acid (PLLA), and poly-methylmethacrylate (PMMA). While fillers are utilized for multiple reasons in the head and neck region, rejuvenating the aging face is the most common. As the demand for fillers increases, it is imperative that the injecting clinician understand the different available products, their rheological properties, and their indications and techniques. Safe injection techniques, along with the knowledge of the actual filler products and the pertinent anatomy allow associated risks to be minimized. As such, this chapter will review the current soft tissue filling agents and address their nuances.