Little is known about cannulation of the vascular access (VA), such as the number of successful cannulation procedures, frequency of complications caused by cannulation, and VA failure. Incident patients were followed for 6 months, from the first successful cannulation with 2 needles--both used for the hemodialysis treatment. Data included patient characteristics, comorbidities, and medication. Vascular access characteristics included: type of VA and location, vein diameter assessed by Duplex ultrasound, length of the cannulation route, and maturation period. Longitudinal data were collected by dialysis nurses, using identical questionnaires, and a standardized method to register data from each dialysis session. Among 10 Dutch dialysis facilities, clinical data from 120 patients were collected from June 2005 to March 2007. The use of autogenous arteriovenous fistulae (P<0.001) and limited length of the cannulation route (P<0.003) negatively affect the outcome of cannulation and complications such as use of single-needle (SN) dialysis and central vein catheters (CVC). Previous use of CVC and SN hemodialysis were significant predictors for VA failure (P<0.0001). The present study demonstrated that during the first 6 months of a newly placed VA, a huge number of cannulation-related complications such as miscannulation, use of CVC, and SN dialysis are encountered. Despite the fact that guidelines recommended the arteriovenous fistulae as the preferred VA, cannulation-related complications can lead to increased morbidity. The length of the cannulation route positively correlates with successful cannulation. Therefore, adjusted cannulation techniques might be indicated to improve VA outcome.