A field survey carried out in 2005 in the Czech Republic and Lithuania to investigate the determinants of converting to organic farming reveals that farmer's own belief and the intrinsic characteristics of the farm increase the likelihood of conversion. If the process of certification as an organic farm implies important changes of the structure of the farm, it lowers the propensity of farmers to consider the conversion to organic. When considering the case of family farms, results of a logit model reveal that apart from farmers' own belief in the environmental or food quality benefits of organic farming, availability of information/own knowledge about the characteristics of technology to be adopted, availability of extra labour, and membership to farmers' associations increase the likelihood to convert.