Abstract. The recent growth in organic farming has given rise to the so-called ''conventionalization hypothesis,'' the idea that organic farming is becoming a slightly modified model of conventional agriculture. Using survey data collected from 973 organic farmers in three German regions during the spring of 2004, some implications of the conventionalization hypothesis are tested. Early and late adopters of organic farming are compared concerning farm structure, environmental concern, attitudes to organic farming, and membership in organic-movement organizations. The results indicate that organic farming in the study regions indeed exhibits signs of incipient conventionalization. On average, newer farms are more specialized and slightly larger than established ones and there is a growing proportion of farmers who do not share pro-environmental attitudes. Additionally, a number, albeit small, of very large, highly specialized farms have adopted organic agriculture in the last years. However, the vast majority of organic farmers, new and old ones included, still show a strong pro-environmental orientation.