The non-natural isotope 90Sr is formed in nuclear reactors and during the explosion of nuclear weapons. This isotope is highly radiotoxic and may lead to leukaemia. Common radioanalytical techniques require analysis time of several days up to three weeks for determination of 90Sr in environmental samples. The aim of this work was to develop a rapid method for the determination of 90Sr in environmental samples using inductively coupled plasma mass spectrometry (ICP-MS). Sample preparation and measurement procedure were focused mainly on overcoming the isobaric interference of the isotope 90Zr, which is present in soils at concentrations higher by more than six orders of magnitude compared to 90Sr. The interfering 90Zr was reduced by a factor of more than 107 in two steps: off-line by ion exchange using a strontium specific resin and directly in the dynamic reaction cell of an ICP-MS by using oxygen as reaction gas. Soil samples from the vicinity of the Chernobyl Nuclear Power plant were used for validation of the developed method. The abundance sensitivity of the inductively coupled plasma mass spectrometer, mainly influenced by the peak tailing of 88Sr on mass 90 u, was studied systematically and found to be about 310-9. A detection limit of 4 fg g-1 (0.02 Bq g-1) was achieved in strontium solutions containing no zirconium. A detection limit of 0.2 pg g-1 soil (1 Bq g-1 soil) was determined in digested uncontaminated soil samples after matrix separation and in a solution of 5 g g-1 strontium and 50 ng g-1 zirconium. 90Sr concentrations in three soil samples collected in the vicinity of the Chernobyl Nuclear Power Plant were determined with the developed method to be 4.66 0.27, 13.48 0.68 and 12.9 1.5 pg g-1 corresponding to specific activities of 23.7 1.3, 68.6 3.5 and 65.6 7.8 Bq g-1, respectively. These results were close to the activities measured earlier by radiometry.