In this study we demonstrate the involvement of ras oncogenes in bladder cancer at the level of RNA overexpression. We examined 26 bladder specimens, consisting of paired tumor and adjacent normal tissue and found that H-ras transcripts were overexpressed in 39% of the specimens while K-ras and N-ras in 58% of total specimens. Each tumor specimen had a unique pattern of overexpression for the three ras genes. A competitive-RT-PCR was employed for H-ras and a beta-actin control gene was co-amplified with K-ras or N-ras genes. These results indicate that the involvement of ras oncogenes in bladder cancer could be relative to overexpression of these genes.