Background: Premature infants are prone to suffer multisystem complications, supportive care bundle is a set of nursing intervention used to improve quality of sleep and physiological parameters of premature infant, which can be affective by environmental stress in neonatal intensive care unit. Aim: This study aimed to evaluate the effects of supportive care bundle on sleep variables and physiological parameters of premature infants and their maternal self-efficacy. Design: A quasi-experimental research design was used for this study. Setting: This study was carried out at the neonatal intensive care unit in Sayed Galal Hospital, affiliated to Al-Azhar University. Sample: A purposive sample composed of 64 premature infants and their mothers after fulfilling the inclusion criteria. The sample was divided into two equal groups, the study and the control groups (32 each). Tools:  Four tools were used in this study: Tool one: A structured interviewing questionnaire, it included three parts: a) Characteristics of premature infants and medical history. b) Characteristics of the mothers. c) Questionnaire to assess the mothers' knowledge. Tool two: Observational checklist to assess the premature infants' sleep variables. Tool three: Physiological parameters assessment of the premature infants by assessing the respiratory rate, heart rate, axillary temperature and oxygen saturation level. Tool four: Perceived maternal parenting self-efficacy questionnaire. Results: The present study revealed that, after intervention, 65.6% of premature infants in the study group had deep sleep compared with 9.4% in the control group. There was an improvement in the physiological parameters of the premature infants after intervention in the study group compared with the control group. There was a highly statistically significant difference between both groups at post intervention (X²=29.067 at P<0.001). Conclusion: The present study concluded that, the implementation of supportive care bundle improves sleep variables and physiological parameters of premature infants, as well as increases mothers' level of knowledge and their self-efficacy scores in the study group than the control group. Recommendations: There is a need to implement strategies of supportive care in NICUs to provide more appropriate premature infant's sleep state and keep stable physiological parameters. Develop an infant care education program for mothers about care of premature infants to improve their knowledge and self-efficacy.