Background: Arteriovenous fistula (AVF) is the preferred access for hemodialysis and choosing a good cannulation technique is a very important factor in preservation of the AVF. There are three different techniques for cannulation of the AVF, the buttonhole technique (BH technique) is considered to be the best choice. Purpose: This study tested if a simple marking on the skin of the direction and angle of cannulation could improve the probability of a successful and pain free cannulation. Material and methods: 83 hemodialysis patients from seven Norwegian hospitals were included from February to March 2012, the study lasted for 8 weeks. All had established AVF and were cannulated with BH technique using blunt needles. Primary outcome was successful cannulation with blunt needles, secondary outcome was level of success seen from nurse’s and patient’s opinion. Patients were also once a week assessed for fear – and painintensity. Results: We found no significant difference in cannulating blunt needles between the groups in the study. We found improvements in cannulating blunt needles within both groups, comparing study week 1 and 2 with week 7 and 8, highest improvements in intervention group (Chi- square t-test, p=0,05). The level of fear1 was lower in controlgroup (t- test between groups, p=0,05), level of pain (VAS) was significant lower in intervention group comparing first/ last period (t- test within group, p= 0,05). Levels of fear/ pain dropped in both groups comparing first - with last weeks, no significance. Infectionrate was at a low level. Conclusions: We did not achieve significant "overall" difference between the intervention - and control group. We did not see an immediate effect of the intervention, but observed the effect coming gradually through the study. The study indicated that the intervention may have a positive effect on the chance of successful canulations, fear and pain, but it is too early to make a clear recommendation.