Monosomy 3 and multiplication of 8q are nonrandom findings in uveal melanoma. We present a case in which two subclones could be detected. Both had monosomy 3 in common. Furthermore, a multiplication of chromosome 8 material was also seen in both subclones. However, it was based on different kinds of aberrations and was accompanied by further anomalies, such as loss of a Y-chromosome, an additional chromosome 7, and an additional marker chromosome, in only one clone. This finding allows some insight into the relevance of the most frequently found anomalies of chromosome 3 and 8 in uveal melanoma. As monosomy 3 occurred before any subclone differentiation, it must be an early, if not primary, event in the genesis of this tumor. Multiplication of chromosome 8, specifically of 8q, however, may contribute to the clonal evolution of this tumor.