This study was conducted to determine the mineral element and protein contents of kernels from different pistachio cultivars at the Damghan Pistachio Research Station, Semnan Province, Iran. Six pistachio cultivars grafted onto Badami Zarand rootstock were evaluated in a completely randomized design with three replications. Three healthy, uniform 25-year-old trees were selected for each cultivar, and 30 nuts were randomly collected from each tree. After kernel separation, samples were oven-dried at 70°C for 48 h, ground, and prepared for mineral and protein analyses. Analysis of variance revealed significant differences among cultivars for all measured traits except copper at the 1% probability level. The highest concentrations of iron (26.6), calcium (1637.6), manganese (8.73), and magnesium (1809.6 mg kg⁻¹) were recorded in the Akbari cultivar. The highest sodium concentration (320.6 mg kg⁻¹) was observed in Khanjari cultivar, the highest zinc concentration (26.37 mg kg⁻¹) in Kaleh-Ghouchi cultivar, and the highest potassium (5741.6 mg kg⁻¹) and phosphorus (2615.6 mg kg⁻¹) concentrations in Germeh cultivar. The lowest levels of sodium, zinc, iron, manganese, and magnesium were found in Abbasali, whereas Shahpasand had the lowest nitrogen, phosphorus, and protein contents, and Akbari had the lowest potassium concentration. Kernel protein content ranged from 15.47% in Shahpasand cultivar to 18.74% in Garmeh cultivar, although differences among Germeh, Khanjari, and Akbari was not significant. Overall, Garmeh, Akbari, and Kaleh-Ghouchi cultivars showed superior nutritional characteristics for several kernel quality traits and may serve as valuable genetic resources in pistachio breeding programs aimed at improving nutritional quality.