Aim: Benign prostatic hyperplasia and prostate cancer is an intationally important health problem of the man, particularly in developed countries. The aim of this exploratory study was to evaluate whether significant difference in the levels of Zn and some other trace elements of prostatic fluid exist between the inflamed and malignantly transformed prostate. Methods: Prostatic fluid levels of Br, Fe, Rb, Sr, and Zn were prospectively evaluated in 52 patients with benign prostatic hyperplasia and 24 patients with prostate cancer. Measurements were performed using 109Cd radionuclide-induced energy dispersive X-ray fluorescent microanalysis. Prostatic fluid samples were divided into two portions. One was used for cytological study to exclude prostatitis, while the other was intended for trace element analysis. Results: Mean values ± standard error of means for concentration (mg/L) of trace element in the prostatic fluid of hyperplastic prostate were: Br 2.32 ± 0.30, Fe 11.5 ± 1.8, Rb 1.70 ± 0.23, Sr 1.41 ± 0.26, and Zn 488 ± 42. The contents of Rb and Zn were significantly lower (approximately 3.2 and 7.7 times, respectively) in fluid of cancerous prostate compared with those in fluid of hyperplastic prostate. Conclusion: There are significant differences in trace element contents in the fluid of hyperplastic and malignantly transformed prostate. The great decrease in levels of Rb and Zn in the fluid of cancerous prostate might demonstrate an involvement of these trace elements in etiology and pathogenesis of malignant prostate tumors. It was supposed that the differences in Rb and Zn levels in prostatic fluid can be used as tumor markers.