The aim of this study is to grade the intraoperative findings seen in carpal tunnel syndrome (CTS) based on severity, and compare it with clinical and electrodiagnostic severity. Thirty-one hands surgically treated for CTS were graded according to the severity of clinical signs, and electrodiagnostic tests. Oedema, vascularisation, and fibrosis were graded on a scale of 1-3. Pseudoneuroma or 'hour-glass' formation were graded as either 0 or 1. The hands were allocated by an observer into an assumptive severity group, from grade 1 to 3. Clinical severity and electrodiagnostic severity were statistically compared with each other, and with each intraoperative severity criteria. A high statistical correlation (p < 0.01) was found between clinical severity and vascularisation, fibrosis, and the assumptive intraoperative severity. No correlation could be demonstrated between electrodiagnostic severity and the intraoperative criteria. Intraoperative grading should be regarded as a supportive measure to the clinical evaluation in order to obtain a sound base for surgical intervention and internal neurolysis.