Every day and every moment, nurses have to deal with a wide variety of patient’s issues and problems, with multiple difficulties and conflicts. Nurse’s judgment considers the core component of healthcare activities. This judgment directs her/his achievement and choices, not for her/him only, but for other healthcare professionals. Thus, nurses have to be competent observers and decision makers with reasoning and sound regarding their intervention and practice. Clinical judgment skills are essential aptitudes in nursing practice, predominantly, in nursing internship intermediary period, in which, a graduate nurse faced several predicaments and obstacles in such transitory experience from academic work to real labor. Aim: to develop a clinical judgment model to guide nursing interns in their nursing practice and assess its effectiveness on nursing interns’ clinical judgment knowledge and skills. Design: Quasi-experimental pretest-posttest research. Sample: A stratified random sampling approach was used to recruit 50 nursing interns as an experimental group. Setting: Damanhur Medical National Institute, El Raee El Saleh, El Farok and Kafer El Dawar Hospitals, in Damanhur, Egypt. Tool: The Clinical Judgment Evaluation Sheet (CJES) by Fathi & Aly in 2018, beside the Lasater Clinical Judgment Rubric (LCJR) by Kathie Lasater et al., in 2009. Results before using the developed model demonstrated that there were observed lacking in knowledge and skills about clinical judgment in nursing practice among experimental group. Then improvements were noticed after using the developed clinical judgment model. These results confirm that the use of an educational and self-learning reference such as the developed clinical judgment model is a successful tool for Egyptian nursing interns in nursing practice. Conclusion and recommendations: There is an understandable deficiency of nursing interns’ clinical judgment knowledge and skills in nursing practice. But, after using the developed clinical judgment model with them as a self-learning reference, it was confirmed that it is a helpful approach to develop and improve clinical judgment knowledge and skills of nursing interns. Creativity in using instructional aides and self-learning approaches is an essential ability that is important among nurse educators and preceptors who direct nursing intern’s performance. For further studies, replicate the study using the developed model with different subjects in nursing practice or develop new instructive models about creative, reflective, discovery, and decision-making models among nursing interns.