The results of a new method for estimating point and diffuse loads of rivers from analysis of monitoring data are presented (immission approach). The estimated point source loads of dissolved nitrogen, total phosphorus, and the heavy metals, cadmium, lead and zinc were compared with the loads of existing inventories. The diffuse loads of these pollutants were compared with estimations calculated on the basis of area related loads of the main diffuse sources (emission approach). Reasonable agreement was obtained in these comparisons, thus demonstrating the utility of the new method as a tool for analyzing point sources and diffuse loads of pollutants to a river system from analysis of monitoring data.