Retinoblastoma is a rare tumor that arise in human retina when both RB gene alleles are mutated. All retinoblastoma have additional genomic changes evident on karyotype and comparative genomic hybridization. We have previously shown a high frequency of the i(6p) marker chromosome and gain of 6p22 in retinoblastoma. We now report a minimal region of 6p22 gain in retinoblastoma that spans 1.2 Mb detected by quantitative multiplex PCR. Using public databases, we determined that the sequence of this region was contained in three contigs. The STS marker with the highest frequency of genomic gain was contained within one fully sequenced PAC AL023807. Exon prediction indicates three unigene clusters within this PAC, one with 19 cDNA sequences in the dbEST. By analysis of those sequences we predicted a partial cDNA sequence, which has homology to the motor domain of the kinesin gene family. We generated several nested PCR primer pairs for rapid amplification of cDNA ends (RACE) and obtained from a retinal cDNA library a previously uncloned kinesin family gene, RBKIN, expressed in retina and included in the region of genomic gain in retinoblastoma. RBKIN is 5,850 bp and is homologous with mouse Kif13a. It is expressed in all adult human tissues tested including retina, as well as retinoblastoma, but its expresion level is very low in most fetal tissues. RBKIN and/or another gene in the same 1.2 Mb of 6p22 are likely to be oncogenes that contribute to initiation and malignant progression of retinoblastoma.