Data are presented on nitrogen isotope composition in ammonium and nitrate from rain-water collected over 2 years in an interior area at Jülich, Germany. The seasonal trends in these data are discussed relative to natural and anthropogenic emissions of nitrogen compounds which additionally have been measured or estimated in their isotope composition, e.g. ammonia from animal urine, fuel combustion, fertilizer use and organic soil nitrogen, and natural and anthropogenic nitric oxides from automobile exhausts as well. The 15N content of Jülich rain ammonium is found to be different from values of Hoering (1957) and Moore (1974) and from other rain samples collected in coastal areas.