hES cells and/or their derivatives are used for the treatment of Osteo-arthritis of the knee and hip joint, said treatment comprising administering 750,000 to 160 million hES cells and/or their derivatives, wherein said cells comprise neuronal stem cell progenitors and/or hematopoietic stem cell progenitors, via intramuscular injection, intravenous injection, or intra-articular injection, or combinations thereof.