To investigate the relationship between inflammatory cells in prostate biopsies and total serum prostate-specific antigen (PSA) levels in a screening population. In the study, transrectal ultrasound-guided prostate biopsy specimens from 49 patients were assessed. All patients undergoing biopsy had elevated serum PSA levels (as defined by the biopsy criteria of the Tyrol PSA Screening Project) and/or abnormal findings on digital rectal examination. The prostate biopsy specimens were histologically negative for carcinoma. Immunohistologic characterization of the inflammatory cells was performed using CD3, CD4, and CD8 antibodies for the detection of T lymphocytes, CD20 antibodies for B lymphocytes, and CD68 antibodies for macrophages. The percentage of inflammatory cells and their distribution in stromal and glandular tissue was estimated using morphometric methods. Inflammatory cells in the stroma contained significantly larger numbers of T lymphocytes than B lymphocytes and macrophages. T lymphocytes were also predominant in the glandular region. A significant positive correlation was found between the relative volume (vol%) of macrophages and total PSA levels (P <0.05) and a significant negative correlation between the percent free PSA levels and the relative volumes of T and B lymphocytes. The results indicate a significant positive correlation between total PSA levels and macrophages and a significant negative correlation between percent free PSA levels and T and B lymphocytes. No statistically significant correlation was found between total serum PSA levels and the presence of inflammatory cells in the stromal and glandular compartment. Additional studies are needed to compare the amount and types of inflammatory cells with the stage and grade of prostate cancer in positive biopsies and radical prostatectomy specimens.