OBJECTIVE: To analyze the populations of prostatic carcinoma lymphoid cells in context of ERG expression. STUDY DESIGN: The material of the study consisted of 122 radical prostatectomy specimens. Immunohistochemistry for CD20, CD45RO, CD4, CD8, and CD56 was performed in a routine manner and the immunopositive cells were counted in the intratumoral, peritumoral, and extratumoral compartments. RESULTS: A total of 67 cases were ERG-positive. They tended to show higher counts of immune cells in comparison to ERG-negative cases, with the highest differences for CD56 as well as intratumoral CD8 cells. CD56 cells were also more numerous in high-grade tumors, similar to CD45RO cells, which were more prominent in cancers with extraprostatic extension. CONCLUSION: With regard to the measured parameters, the counts of lymphoid cells in the ERGnegative group were lower than those in the ERG-positive group but did not reach statistical significance. © Science Printers and Publishers, Inc.