The objectives of this study were to identify the influencing factors and suggest guidelines for improving the technological effectiveness of spin-offs concerning the national nuclear R&D programmes in Korea. in order to find the influencing factors on the technological effectiveness of the spin-off process, this study described the conceptual model which was composes of the technological effectiveness and three-group influencing factors such as donor, recipient and common factors. To; validate the conceptual model, data were collected from twelve cases through in-depth interviews and well-prepared questionnaires, and the Spearman's correlation coefficient was employed Finally, the influencing factors at each stage of the spin-off process were integrated to draw up a schematic framework and evaluate the implications for the improvement of technological effectiveness of spin-offs.