[en] The Biospheric Model Validation Study (BIOMOVS) is an international cooperation study on testing of models to predict the distribution and accumulation of radioactive and other toxic substances in the biosphere. The main objectives of the study are to compare and test the predictions, recommend priorities for future development concerning the improvement of the models. The international cooperation initiated in 1985 by the Swedish National Institute of Radiation Protection (NIRP), Stockholm is involved in two kinds of approaches. Approach A means to test model predictions against independent sets of real data. Approach B, on the other hand, aims to compare model predictions obtained from the different models for specific test scenarios. The first phase of the BIOMOVS lasted until 1990, the BIOMOVS II should begin in 1991