Background: Quality of patient care is enhanced by effective communication between nurses and patients. One of the most important management practices to improve the quality of nursing care is applying nursing care delivery systems by nurse managers especially by head nurses effectively,

Aim:  this study was done for comparing the effectiveness of primary nursing care and case method on quality of nurse-patient interaction in CCU.

Methods: This study was a quasi-experimental study that was done in four CCU in two teaching in Mashhad in 2014. Two units for case method (n=26 patients) and two units for primary nursing (n=33 patients) randomly selected.  In implementation, at first all of the nurses trained with two nursing care delivery systems by workshops. And then, in primary system allocated (3) patients to primary nurse who was responsible to their discharge. In other shifts sh/he supervised him/her associate nurse. Also, in case method, head nurse allocate (3) patients to nurses in the shift, only they were here. All of the policies established that were needed by head nurse mutually. Both of two nursing care delivery systems implemented for (2) months. Data were gathered by standardized questioner QUAL-PAC) Quality of patient care) that its reliability was measured by &alpha-Chronbach (0.89). Data were analyzed by SPSS₁₆ and statistical tests such as Mann-Whitney, c² and others were used.

Results: findings showed that there is a significant difference between two group (case method and primary nursing) in quality of interaction between nurses- patients (p <0.00001). So, the mean of quality interaction in primary nursing was higher (35.3±8.3) than the other method (24.4±5.7). Also, there is not any correlation between job experiences' nurses and quality of interaction (p =0.17).

Conclusion:  In order to effectiveness primary nursing care in promotion in quality of interaction between nurse- patients, it is suggests to nurse managers that they apply its model in CCU.