Background: Overt hepatic encephalopathy (HE) following insertion of a transjugular intrahepatic portosystemic shunt (TIPS) is a problem in some patients. In contrast to overt HE, minimal HE (MHE) following TIPS is studied to a limited degree only. We therefore evaluated the incidence of MHE in patients following TIPS insertion by determination of the critical flicker frequency (CFF). Methods: 45 cirrhotic patients (Child A/B/C: 7/24/14; Child-Pugh score 8.5 � 2.0) underwent TIPS because of recurrent esophageal bleeding (n = 15), refractory ascites (n = 25) or a combination of bleeding and refractory ascites (n = 5). Hemodynamic parameters were recorded during TIPS insertion. CFF was determined using a portable analyzer 2 days before and 3, 28 and 84 days after TIPS. At these time points the number connection test and biochemical markers were recorded as well. Results: TIPS led to a reduction of the portal pressure gradient from 19.1 � 5.9 to 9.3 � 6.1 mm Hg together with a slight but significant increase in bilirubin from 1.5 � 0.9 to 2.2 � 1.9 mg/dl and in the international normalized ratio from 1.2 � 0.3 to 1.4 � 0.5. Creatinine decreased from 1.3 � 0.6 to 1.1 � 0.5 mg/dl. Pre-TIPS, 27 patients had normal CFF (>38 Hz, CFF 41.1 � 2.4 Hz) and 18 patients had altered CFF (?38 Hz, CFF 34.4 � 3.0 Hz): 3 had grade I and 15 MHE. Three days post-TIPS, 3 of the 27 patients (11.1%) with normal CFF deteriorated to MHE, 1 of the patients with grade I HE deteriorated to grade II HE, 1 maintained grade I HE and the other improved. No patient with MHE deteriorated to overt HE. Conclusions: Using the determination of the CFF, we were able to show that elective TIPS insertion in patients with preserved liver function causes a MHE in only the minority of patients. In addition, patients with preexisting MHE did not deteriorate to overt HE.