The prognostic value of various subjective and objective noninvasive urological parameters was evaluated for their possible role in the prediction of post-hernioplasty urinary retention. In a prospective study, 35 patients aged 55-85 years without previous micturition complaints or urological surgery were evaluated 1 day prior to inguinal hernioplasty. This included medical history for modified Madsen subjective scoring profile, physical examination and uroflowmetry. Bladder capacity, residual urine and prostatic volume were measured by ultrasound. All patients underwent a similar method of hernioplasty, were closely followed 48 h postoperatively and any voiding difficulties or urinary retention were noted. Urinary retention occurred in 12 patients. None of the remaining 23 patients had urination difficulties. Comparing these two groups, we concluded that patient age, bladder capacity and prostatic volume have no prognostic value for potential postoperative urinary obstruction. On the other hand, obtaining a good anamnesis of obstructive and irritative symptoms for scoring, measuring maximal flow rate on urinary flowmetry and estimating residual urine volume may predict patients who are potentially at high risk for posthernioplasty urinary retention.