Objectives: to study the relationship between prostate specific antigen and Qmax of uroflowmetry in patients over fifty years old who are suspected to have benign prostatic hyperplasia. This study was not done before as no one studied the relationship between these two items. Methods: our study was a prospective study conducted upon one hundred male patients, all of them above the age of fifty. Between February 2008 and February 2009, the patients under the study were attending outpatient clinic in Kasr El Aini Cairo University hospital complaining of lower urinary tract symptoms either irritative, obstructive or both. History was taken from all patients; all patients were examined by DRE and abdominal examination. We performed pelvic ultrasonography, serum PSA estimation and uroflowmetry to all patients. We calculated the volume of residual urine for all patients by pelvic ultrasonography. We performed TRUS and biopsy for patients with PSA more than 4 ng/ml. Results: after collecting all these data from the one hundred patients, we correlated all data to find any significant correlations. Correlation was done between the age of the one hundred patients, their prostate size,volume of residual urine, Qmax of uroflowmetry and serum PSA value. The serum PSA level increased with an increase in the volume of residual urine. Furthermore, the serum PSA level increased with the age of the patient. The volume of residual urine increased with larger prostate sizes. Qmax of uroflowmetry negatively correlated with prostate size.Conclusion: there was no significant relation between serum PSA level and Qmax of uroflwmetry in patients with lower urinary tract symptoms.