Introduction: Premature birth is highly stressful for parents. Nursing support is crucial for premature infants. Parental satisfaction is a vital indicator of the quality of care provided by nurses. Therefore, determining the factors related to parental satisfaction is important in nursing care. Objective: This study aims to investigate the relationship between social support and parentschr('39') satisfaction with the medical care provided to their premature infants in the Neonatal Intensive Care Units (NICUs). Materials and Methods: This is an analytical/correlational study. Participants were 130 parents of premature infants admitted to the NICUs in three hospitals affiliated to Tehran University of Medical Sciences in Iran. They were selected based on a convenience sampling method. Tarkka’s Social Support Questionnaires and the Neonatal Index of Parent Satisfaction were used for collecting data. Data were analyzed by using descriptive statistics and T-test, Chi-square test, ANOVA and Pearson correlation test. Results: It was reported that 55.38% of the infants were females, with a mean birth weight of 1880.97± 544.85 gr and a mean gestational age of 32.07±2.41 weeks. The mean age of their mothers and fathers was 31.25±5.12 and 35.03±5.66 years, respectively. The highest level of social support in mothers and fathers was related to emotional support (3.65±0.69 in mothers and 3.29±0.57 in fathers), while the lowest level of social support was related to concrete support (3.32±0.80 in mothers and 3.16±0.65 in fathers). Mothers perceived higher social support than fathers. They also had more satisfaction with medical care (3.88±0.81 in mothers and 3.63±0.69 in fathers). There was a significant relationship between social support and parental satisfaction (r=0.791, P<0.05). Conclusion: Parents of premature infants need more social support, especially concrete aid. Therefore, planning to promote social support of parents, especially fathers, by nurses in the NICUs seems necessary.