Introduction: We estimated the diagnostic accuracy of Abrams-Griffiths number (AG), urethral resistance factor (URA) and detrusor-adjusted mean passive urethral resistance relation factor (DAMPF) for bladder outlet obstruction (BOO) in benign prostate hyperplasia (BPH) patients. Materials and Methods: AG, URA and DAMPF were obtained by pressure-flow studies from BPH patients. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic accuracy of the AG, URA and DAMPF in the diagnosis of BOO. Results: Among the 172 cases there were 154 classified as obstructed (89.5%) and 18 as unobstructed (10.5%). There were statistically significant differences in AG, URA and DAMPF between the obstructed and the unobstructed cases. The ROC curve demonstrated a similar diagnostic accuracy in the diagnosis of BOO for AG and URA values, and the least was seen for the DAMPF value. An AG cutoff of >33 provided a sensitivity of 89.61% and a specificity of 100%. A URA cutoff of >28 provided a sensitivity of 91.56% and a specificity of 100%. A sensitivity of 93.51% and the weakest specificity of 77.78% were recorded for DAMPF values of >52. AG and URA had a similar accuracy, while the efficacy of DAMPF is significantly lower in the diagnosis of BOO. Conclusions: AG or URA appeared to be the best discriminating parameters of BOO in BPH patients. The DAMPF could be used to aid the BOO diagnosis. Lower cutoff values were suggested for these BOO parameters. Copyright (C) 2010 S. Karger AG, Basel