This study designed an organic farmer's behavior model based on the Ajzen’s theory of planned behavior. The methodology was Mixed Method Research. In the qualitative phase, ten rice producers who received healthy product certification from Standard Organization were interviewed. The results of qualitative research showed that factors affecting the organic farming conversion consisted of facilitating factors and barriers. Facilitating factors include motivations and profits and barriers include challenges and costs. In quantitative phase, 250 rice producers were randomly interviewed. The results of quantitative research showed that attitude and subjective norms of rice producers have a significant positive effect on their intension toward organic farming. Ajzen’s model has been improved by adding variables such as knowledge, self-identity and moral obligation . As a result, the model is improved and approximately 92 % of the variance of rice producers’ behavior in organic farming is explained by research variables.