Temporal trends in organ donor harvesting rates are subject to variability. It is important to detect variations as early as possible using current data. We developed a predictive model for monitoring harvesting activity using the number of donors harvested monthly between 1996 and 2001. A Poisson model was used to predict the number of donors harvested each month along with their confidence intervals. This model also updates, on a monthly basis, the predicted number of donors for the current year. During 2002, the number of donors observed each month followed the predicted monthly variations, but a significant increase was observed in March and May. These models can be used by transplantation agencies for monitoring purposes and for the evaluation of organ donation programmes.