We present some results on the ion composition and acidity of rain and snow precipitation in Novosibirsk Region (south of the Western Siberia) obtained during the period from 2000 until 2005. Seasonal variations in mineralization, acidity, concentration, and a fraction of some ions in precipitation were considerable. We can conclude that the main sources of ions in precipitation are the continental aerosol particles, and an additional source of NH4+ is the gaseous NH3. Activity of the first one is enhanced in winter whereas that of the second in summer. Precipitation acidity increases when its mineralization reduces. Rainfalls acidity (mean value of pH equal 5.55) is somewhat higher than that of snowfalls (pH equal 5.87), but overall it remains close to the standard level (pH equal 5.8). The results are compared with similar data obtained at the same observation sites during the period from 1996 until 2001 as well as with the data for other regions in Russia and in the World.