One representative pilot study area (PSA) was selected on the territory of Moldova. On this PSA special boreholes were drilled up including unsaturated zone and first water-bearing horizont.Chemical elements inluding major anions and cations, and nitrate, TDS, pH were deternimed in the samples. The content of the residual amounts of pesticides including chlororganic (DDT, DDD, DDE, GHCG), phosphororganic (fozalon, fasfamid, metaphos), simmetric triazines (atrazin, prometrin, simazin) and trephlan were studied. Under the influence of irrigation geochemistry of the unsaturated rocks is changed. Analysis of the statistical parameters and correlation coeffisients of the chemical elements shows that K+, Cl- and NO3 and TDS are the geochemical indicators of the zone of aeration (unsaturated). The contents of these elements is elevated compared with background boreholes. The maximum depth of the geochemical changes makes 2.5 – 3.0 m. Pesticides were detected in all intervals of the unsaturated zone and ground water. Theire contents, with exeption of fozalon are smaller than the limits of the sanitary rates establlished. 2 – 4 pesticides may be detected in one sample, these being most stabe and toxic. According to the occurrence frequency pesticides can be ordered as follows: GHCG>fozalon>DDE(DDD,DDT, rogor)>sim m-triazines. Pestisade migration in the unsaturated zone is in a small depth range of 0.0 – 3.0 m. Decreasing of the pesticide concentration is a exponential function with maximun near land surface and minimum at the indicated depth. Data of the present study will be used for the modelling of pesticides in the unsaturated zone.