In this report the results are presented of the measurements of the chemical composition of precipitation in the Netherlands carried out in 1991. This took place by means of the 4-weekly samples obtained from the National Precipitation Chemistry Monitoring Network (LMRe), which consisted of 14 stations in 1991. Samples were taken at all stations to be analysed for main components and inorganic microcomponents (heavy metals). Additionally, at three stations samples were taken to be analysed for organic microcomponents. Analysis of the main component samples determined the concentrations of hydrogen ions (free acid), sodium, potassium, calcium, magnesium, fluoride, chloride, nitrate, sulphate, bicarbonate and phosphate; the conductivity and the pH value of these samples were also determined. The samples for heavy metals were analysed for cadmium, copper, iron, manganese, nickel, lead, vanadium and zinc. Furthermore, arsenic, chrome and cobalt were determined in the samples from three stations. The analysis spectrum of the organic components included the components alpha-hexachlorhexane (alpha-HCH), gamma-hexachlorhexane (gamma-HCH), hexachlorbenzene (HCB), and thirteen representatives from the group of polycyclic aromatic hydrocarbons (PAHs). Chapter 1 contains information about LMRe. In Chapter 2 the calculation procedures used here are described. In Chapter 3 the presentation of the results in the appendices is explained.