Malignant melanoma poses a serious health risk which is becoming more crucial as the incidence of this disease steadily increases. The development of appropriate in vitro models that reflect the in vivo tumor environment is a key factor for the study of this malignancy. The local tumor microenvironment plays a critical role in the ability of tumor cells to proliferate and metastasize. While interactions among various cell types are known to be important for tumor growth, most in vitro models utilize only tumor cells, ignoring the importance of tumor–stroma interactions, as well as the contribution of immune cells, which may be important for potential therapies. In addition, the cellular architecture found in vivo, known to be involved in changes in gene expression, is not reflected in standard two-dimensional culture systems. In this study, we have utilized rotating-vessel bioreactors to culture minced human melanoma specimens, allowing the culture of three-dimensional structures which reflect the cellular architecture and heterogeneous composition of the tumor site in vivo. The viability of the pieces in culture can be maintained for 1–2 wk. Immunohistochemical analysis shows multiple cellular types similar to the in vivo situation. Therefore, this system provides a unique model of human melanoma that mimics the in vivo tumor environment much more closely than current culture methods. This novel system may be utilized to determine the mechanism of action of current therapy protocols, as well as to develop new treatment regimens.