To assess the accuracy and validity of true net corneal power of the Pentacam system to provide a keratometry reading for calculating intraocular lens (IOL) power in postoperative refractive surgery eyes. Refraction, an automated keratometry reading, and true net corneal power were measured for 30 eyes that required cataract surgery and had previously undergone refractive surgery. Target refraction values calculated with the SRK/T formula using true net corneal power were compared with postoperative manifest refraction values. Using true net corneal power, the mean deviation from the desired postoperative cataract refractive outcome was 0.47 +/- 0.56 diopters (D); the actual refraction was within +/- 0.50 D of the intended refraction for 70% of eyes (21/30) and within +/- 1.00 D for 93% of eyes (28/30). The true net corneal power can be used as a keratometry reading for eyes with previous refractive surgery requiring cataract surgery.