Vascular catheter use for dialysis remains highly prevalent, however, it is frequently adversely affected by access recirculation (AR). We previously reported the utility of effective ionic dialysance (EID)/blood flow rate (Qb) ratio in identifying significant (>5%) AR in arteriovenous (AV) fistulas (Mohan et al ASAIO J 56:427-433, 2010). We present data from 58 patients, receiving hemodialysis via venous catheters (85% tunneled cuffed catheters) who underwent intermittent monitoring for AR with the saline dilution technique (Transonic HD02 monitor) and had EID and Qb measurements from Diascan biosensor in the Gambro Phoenix dialysis machine available. Among the 193 hemodialysis sessions studied, 74 instances of significant access recirculation (sAR) were identified. A higher incidence of sAR occurred with temporary catheters and catheters in the femoral vein. We report a significant correlation between the EID/Qb ratio and AR in addition to demonstrating the predictive utility of the ratio for identifying dysfunction catheters with sAR (area under the receiver operator characteristic curve of 0.86 with a sensitivity of 79% and a specificity of 76% at an EID/Qb ratio of ≤ 0.60). Our data demonstrate the utility of the EID/Qb ratio as an indicator of sAR in dialysis catheters albeit at a different threshold than that seen with AV fistulae.