The objectives of this study were to investigate the degrees of emotional labor, the effects to organizational effectiveness and the significant factors influencing organizational effectiveness in radiation therapy professional. The subjects of this study were the radiation therapists working at the hospital in Seoul and Gyungi. The self-reported questionnaires were administered to 205 radiation therapists and the data were analyzed with SPSS 19.0 package. The level of emotional labor of single or female subjects were revealed higher than married or male. The professionalism of job has significant correlation with emotional labor. Significant explanatory variables of the degrees of emotional labor included organization culture, distress and self-leadership. These three variables demonstrated the explanatory power of 13.9% of the emotional labor. Based on the findings, emotional labor of radiation therapist was correlated with occupational professionalism. These results suggest that the intervention program intervening emotional labor should be continued to develop in order to improve the effective self-leadership, organization culture and distress factor.