Objective: The aim of the study was to determine the correlation of the causative agents of prostatitis and orchiepididymitis with the age of patients in order to better understand their occurrence within different age groups. Study design: The study is designed as a cross-sectional study with historical data. Participants and methods: The study included patients of the Department of Urology of the Clinical Hospital Center Osijek, who were treated inpatient, outpatient and in daily hospital of the Department of Urology from January 1st to June 1st 2019. The study included all patients diagnosed with acute or chronic prostatitis and acute or chronic orchiepididymitis. An encryption system was introduced in data collection and it is not possible to determine the identities of persons whose data were used in the research. Results: Of the total number of patients with prostatitis (256), 91 (35.5%) were diagnosed acute and 165 (64.5%) with chronic prostatitis. Causal pathogens were found in urine culture and ejaculate findings in 56 patients. Escherichia coli was isolated in 35 cases (62.5%), mostly in patients older than 35, while in older men of the median age of 73 and the interquartile range from 68 to 86 years of age, we found Enterococcus faecalis. The presence of Escherichia coli was observed in patients with acute orchiepididymitis older than 35 years. There were no patients diagnosed with chronic orchiepididymitis. Conclusion: An increasing presence of Escherichia coli was observed in older and younger population and an increasing presence of Enterococcus faecalis was found in elderly patients.