Rationale and aims To evaluate the extensive use of peripheral venous catheters (PVCs), including catheter-related complications, a reliable tool for PVC assessment is needed. The aim of this study was to develop such a tool to evaluate PVCs in relation to management, documentation and signs and symptoms of thrombophlebitis (TH), as well as to determine its inter-rater and test-retest reliability. Method The tool development included confirmation of content and face validity. Two groups of registered nurses used the new tool (PVC assess) to assess PVC management and signs of TH independently. Group A (n = 3) assessed 26 items in 67 PVCs bedside (inter-rater reliability). Group B (n = 3) assessed photographs (67 PVCs, 21 items) of the same PVCs as those in Group A with a 4-week interval (test-retest reliability). Proportion of agreement P(A) and Cohen's kappa were calculated to evaluate inter-rater and test-retest reliability. Results Among nurses assessing PVCs at bedside, the P(A) was good to excellent (0.80-1) in 96% of the items in PVC assess. In 80% of the items kappa was substantial to almost perfect (0.61-1). TH sign erythema fell into the fair range (kappa = 0.40). In test-retest reliability analysis the P(A) was within the good and excellent range (0.80-1.0) and kappa varied from moderate to almost perfect (0.41-1.0) in 95% of the items. One item 'outer dressing is clean' was in fair range (0.21-0.40). Conclusions The PVC assess instrument shows satisfactory inter-rater and test-retest reliability. Reliability tests on reviewing documentation remain to be performed.