This retrospective cohort study from a single clinical practice enrolled patients with evidence of calcified Peyronie's disease (PD) plaques detected on penile ultrasound at the time of initial presentation. The primary objective was to describe the effect of pentoxifylline (PTX) treatment on subtunical calcifications in men with PD. A PD-specific questionnaire was administered and sonographic evaluations were performed at baseline and follow-up visits. Descriptive statistics and χ(2) analysis were used to characterize the effect of PTX on calcified tunical plaques. In all, 71 men (mean age: 51.9 years) with PD and sonographic evidence of calcification were identified. Of them, 62 of these men were treated with PTX for a mean duration of 1 year, and nine with vitamin E or no treatment. Improvement or stabilization in calcium burden at follow-up was noted in 57 (91.9%) of men treated with PTX versus four (44.4%) of those not treated with PTX (P<0.001). PTX users were much less likely to have a subjective worsening of their clinical condition (25.0% versus 78.3%, P=0.002). Treatment with PTX appeared to stabilize or reduce calcium content in PD plaques. A randomized controlled trial is warranted to further explore this effect.