Display omitted •Few studies have examined the effects of Ca nano-fertilizers on pomegranate fruit yield and quality.•Fruit yield and quality of pomegranate trees have been assessed after two sprays with different Ca formulations, including a nano-fertilizer and CaCl2.•Ca foliar fertilization had no effects on pomegranate yield and only small effects on fruit quality.•A positive effect of Ca fertilizers in decrease pomegranate fruit cracking was found.•Low doses of a Ca nano-fertilizer were better than high doses of CaCl2 in reducing pomegranate fruit cracking. An experiment was conducted to assess the effects of foliar sprays of a calcium fertilizer containing nanoparticles (nano-Ca) and calcium chloride (CaCl2.2H2O) on the yield and quality of pomegranate fruits cv. Ardestani, during two consecutive years, 2014 and 2015. The nano-Ca fertilizer was sprayed at concentrations of 0.25 and 0.50g Ca L−1, and CaCl2.2H2O was used at concentrations of 1 and 2% (2.73 and 5.45g Ca L−1), with treatments being applied twice, first at full blooming and then one month later. Calcium foliar fertilization did not have significant effects on yield, number of fruits per tree and average fruit weight, whereas it increased fruit length only in the case of the CaCl2 1% treatment in the first season. The untreated trees in the orchard were moderately affected by fruit cracking, with 6–7% of the fruits being affected. Calcium foliar treatment with the nano-Ca fertilizer at 0.50g Ca L−1 and 1% CaCl2 (in the both seasons) and also 2% CaCl2 (only in the second season) decreased significantly fruit cracking when compared with the control treatment, resulting in increases in marketable fruit yield. Foliar sprays with CaCl2 1% increased TSS by 7.6% only in the second season. Moreover, foliar nano-Ca fertilization at 0.50g Ca L−1 led to minor decreases (approximately 1%) in total phenolics only in the first season. Other chemical properties, including titratable acidity, fruit maturity, total sugar, antioxidant activity and total anthocyanin contents were not affected by Ca foliar fertilization. Leaf analyses show that Ca foliar treatments increased leaf Ca concentrations in the first season, with the exception of the low dose of nano-fertilizer, whereas the leaf concentrations of N, P, K, Fe, Zn and Mn were unaffected. In summary, fertilization with a low (0.50g Ca L−1) Ca concentration in the form of a nano-Ca formulation resulted in similar decreases in pomegranate fruit cracking than those obtained with higher doses of CaCl2 (2.73 and 5.45g Ca L−1).