Abstract Bye writing this review I intend to answer these three self-defined objectives: 1. Of the five different thrombospondins (TSP), which are present in articular cartilage (AC)? 2. What does the research literature say about TSP function in AC? 3. Could the different TSP have any practical use for cell cultures consisting of either chondrocytes or mesenchymal stem cells? Introduction: AC is known as a highly specialized tissue as it has neither blood vessels, nerves or any self-repair. In synovial joints is AC known to be the main structure that both cushion load and smoothens the joint surfaces during movement. These traits of the AC are known to be dependent on the extracellular matrix that mainly consist of collagen type II (KOL II), aggrecan, water and other proteoglycans and glycoproteins. One of the most known glycoproteins in AC is Cartilage oligomeric matrix protein (COMP). COMP is also known as TSP5, and is one of five matricellular proteins which constitutes the protein family know as TSP. The other are TSP1, TSP2, TSP3 and TSP4. As matricellular proteins, they are known to regulate cell and tissue phenotype through interactions with either the ECM proteins, the cells of the tissue or both. Further, both TSP1 and TSP2 is known to be antiangiogenic. This makes these proteins interesting in the context of AC. Method: The method used in this review was a step-by-step approach which had three main steps: 1. Define the main objectives. 2. Search for literature in Medline with different search strings based on my objectives. 3. Answer the first objective first before new searches with search strings is made considering the other two objectives. Results: The main results for this review were: 1. TSP1 and TSP5 are shown at the protein level to be present in human AC, and all TSP were shown to be expressed at the gene level in AC from minipigs (Jeschke et al., 2015). And most likely is also TSP4 secreted as proteins to the ECM of AC (Brachvogel et al., 2013; Jeschke et al., 2015). 2. By highlighting and discussing acquired literature it was shown that TSP1 and TSP5 most likely have several functions in AC. Most important, the acquired literature identified TSP1 as an important antiangiogenetic factor in AC. And for TSP5 was it shown that this protein most likely had a protective role in AC by interacting with the KOL II fibrils, is a catalyst for fibrillogenesis and much likely also had a regulatory role in OA. 3. Both TSP1, TSP2 and TSP5 could all have practical use in cell cultures containing chondrocytes and MSC since they all the potential to improve already induced chondrogenesis. And TSP5 is already in use as a phenotypic marker of differention state in cultures consisting of chondrocytes. Discussion: The discussion is separated in two parts. In the first part are the results discussed and the main findings presented. Further is the results compared with the known literature presented in the introduction. In the second part is the method used in this review discussed. Further are the findings of this review quite often presented as most-likely results. The reason is that the study setups often used to analyze matricellular proteins more often than not analyses the direct interactions between proteins and cells and therefor often end up having less impact when the biology of tissues is discussed. This is also the fact for several of the papers I have discussed in this this review. Conclusion: 1. TSP1 and TSP5 are validated to be present at the protein level in human AC, and likely is also TSP4 present at protein level. 2. Anti-angiogenesis has been shown to be one the main effects of TSP1 in AC and TSP5 has been shown to protect the microfibrillar collagen network in AC through an interaction with KOL II, an interaction which also most likely regulate the OA process. 3. Both TSP1, TSP2 and TSP5 have the potential to be used in cell cultures containing either chondrocytes or MSC. This reflects on presented data that show that TSP1 have the potential to inhibit induction of hypertrophy and that TSP2 have been shown to have the potential to induce chondrogenesis in MSC. And further, TSP5 has been shown to be an ideal marker for differentiation state of chondrocytes and MSC.