Metallothionein (MT) is a metalloprotein that has high affinity for heavy metal ions such as cadmium (Cd), copper, and mercury. We investigated the induction of MT expression by zinc (Zn) treatment of the cartilage precursor ATDC5 cell line using quantitative reverse transcription-polymerase chain reaction analysis. Cell viability and toxicity were examined by a WST-8 assay and lactate dehydrogenase assay, respectively. Zn treatment induced the expression of MT, which involved the differentiation of the ATDC5 cell line into chondrocytes. Treatment of ATDC5 cells with Cd caused a significant reduction in cell viability. However, following Zn pretreatment, there was no decrease in cell viability or differentiation on Cd treatment. Our study indicates that the induction of MT expression by Zn in cartilage precursor cells reduced Cd-associated cell toxicity.