**1. Introduction**

Cartilage is one of the critical tissues existed in human and animal bodies, such as rib cage, ear, nose, bronchial tubes, intervertebral discs, meniscus, and the joints between bones [1]. Cartilage injuries are the most common diseases. According to National Health Interview Survey (NHIS), in 2010–2012, about 52.5 million adults in the USA had doctor-diagnosed arthritis, and by 2040, the number of US adults with doctor-diagnosed arthritis is projected to increase 49% to 78.4 million. That means about 25.9% of all adults have arthritis [2, 3]. Degeneration of the intervertebral disc, a fibrocartilaginous joint residing between adjacent vertebrae in the vertebral column, is the most frequent cause of low back pain and another significant cartilage-related disease [4]. The overall cost of chronic low back pain exceeds the combined costs of stroke, respiratory infection, diabetes, coronary artery disease, and rheumatoid disease [5]. However, the damaged cartilage has little ability for repairing itself due to the lack of blood supply, nerves, and lymphangion [1], and the effective therapeutic treatments for cartilage regeneration are very few.

Tissue engineering is an interdisciplinary field that applies the principles of engineering and the life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function [6]. Stem cells, scaffold, and biologic active molecules are three key components in tissue engineering [7]. Successful tissue engineering relies on multiple factors including obtaining appropriate cells for implantation, directing the development of those cells on an appropriate differentiated pathway using growth factors and/or cytokines, supporting the growing cells on a three-dimensional matrix, and having that matrix remains in the injured tissue area, at least until healing is completed [6, 8]. This book chapter highlights the recent developments of tissue engineering approaches including stem cells, biomaterials, bioactive compounds, and reagents used for cartilage regeneration and repair.
