1. Urinary excretion of endothelin-1-like immunoreactivity and urinary excretion of other parameters (beta 2-microglobulin, N-acetyl-beta-D-glucosaminidase and microalbumin) were measured before, within 1 week after and 2 weeks after the administration of cis-platinum in five young male patients with testicular cancer (mean age 33.0 years) and were compared. 2. Urinary endothelin-1-like immunoreactivity/creatinine during, 1 week after, and 2 weeks after cis-platinum treatment was significantly higher than before cis-platinum. There was no difference in urinary endothelin-1-like immunoreactivity/creatinine during, 1 week after and 2 weeks after cis-platinum. 3. Among the four parameters, urinary endothelin-1-like immunoreactivity/creatinine showed the highest level after cis-platinum treatment. Urinary beta 2-microglobulin/creatinine most rapidly returned to normal levels after cis-platinum. 4. Although urinary endothelin-1-like immunoreactivity/creatinine did not show any significant correlations with urinary N-acetyl-beta-D-glucosaminidase (r = 0.291, not significant) or urinary microalbumin/creatinine (r = 0.076, not significant), it showed a significant correlation with urinary beta 2-microglobulin/creatinine (r = 0.475, P < 0.05). 5. These results suggest that endothelin-1 may be a sensitive urinary parameter in detecting cis-platinum-induced renal tubular injury.