Background: A classification model was developed to simplify planning of personnel at dialysis centres. This model predicted the care burden based on dialysis characteristics. However, patient characteristics and different dialysis centre categories might also influence the amount of care time required. Objective: To determine if there is a difference in care burden between different categories of dialysis centres and if specific patient characteristics predict nursing time needed for patient treatment. Design: An observational study. Participants: Two hundred and forty-two patients from 12 dialysis centres. Measurements: In 12 dialysis centres, nurses filled out the classification list per patient and completed a form with patient characteristics. Nephrologists filled out the Charlson Comorbidity Index. Independent observers clocked the time nurses spent on separate steps of the dialysis for each patient. Dialysis centres were categorised into four types. Data were analysed using regression models. Results: In contrast to other dialysis centres, academic centres needed 14 minutes more care time per patient per dialysis treatment than predicted in the classification model. No patient characteristics were found that influenced this difference. The only patient characteristic that predicted the time required was gender, with more time required to treat women. Gender did not affect the difference between measured and predicted care time. Conclusion: Differences in care burden were observed between academic and other centres, with more time required for treatment in academic centres. Contribution of patient characteristics to the time difference was minimal. The only patient characteristics that predicted care time were previous transplantation, which reduced the time required, and gender, with women requiring more care time.