To screen all of our patients being treated with intrathecal baclofen (ITB) therapy for catheter patency. Catheter patency was examined by performing a catheter access port study in 91 pediatric and adult patients undergoing ITB therapy at our institution. Despite no preoperative clinical suspicion of a problem with the ITB system in all but one case, 16.5% of the catheters in our patient population were not patent. After replacement, prerevision and stable postrevision dosage was examined to determine the impact system replacement had on the daily dosage. There was a significant 65% reduction in the daily ITB dosage from before catheter exploration (M = 823.8 mcg/day, SD = 390.51) to stable post replacement/revision dosage after catheter replacement or revision (M = 289.43 mcg/day, SD = 187.76), t = 4.09, p = .002, 95% CI 246.80, 822.00. These results suggest that catheters need to be routinely screened for patency. Routine maintenance and screening can minimize or more quickly detect nonpatent systems and ensure proper functioning of the ITB system.