Priapism is thought as a condition of penile erection that persists beyond or is unrelated to sexual stimulation. Commonly two different entities of priapism are known, one is low-flow priapism and the other is high-flow priapism. It is important to distinguish these two conditions for the subsequent different treatments. We report a rare case of an indistinguishable priapism caused by penile metastasis of testicular cancer.