There is good agreement between dermatological staff and patients using the Hand Eczema Extent Score (HEES). The aim of this study was to assess inter- and intra-observer reliability of the HEES in dermatologists and intra-observer reliability of the HEES in patients with hand eczema. Six dermatologists assessed 18 patients twice. Only the hands of the patients were visible to the assessors. Patients performed a self-assessment twice. Inter- and intra-observer reliability was tested with intraclass correlation coefficient (ICC). The mean HEES score for all dermatologists' assessments was 21.0 (range 3.6-46.3). The corresponding mean scores for all patients' own assessments were 24.9 (range 4.0-54.0). Inter-observer reliability in the dermatologists' observations ICC classification was very good, median value 0.82 (range 0.56-0.92). The overall intra-observer reliability for the 6 dermatologists' ICC classification was very good (range 0.88-0.94). Intra-observer reliability in the patients' 2 self-assessments ICC classification was very good (ICC 0.95). In conclusion, HEES is a reliable tool for both dermatologists and patients to grade the extent of hand eczema.