Cancer is a worldwide conundrum and the leading cause of death. Drug delivery to cancer cells has been changed thanks to nanotechnology. In this study, calcium carbonate nanoparticles were used to provide Vitamin D to the breast cancer cell line MCF-7. The nanoparticles that are used, were prepared by using binary solvents as precipitates and swirling them continuously with a magnetic stirrer. FTIR and XRD measurements confirmed the production of nanoparticles. SEM analysis revealed that nanoparticles have a spherical morphology. According to a UV-Visible spectrophotometer, calcium carbonated nanoparticles had an encapsulation effectiveness of 80% for vitamin D. At a dosage of 2000g/ml, vitamin D conjugated nanoparticles showed a good cytotoxic activity, reducing the viability percentage of cancer cells by up to 11%. As a result, it was found to be helpful in slowing cancer cell development. The findings showed that CaCO3 nanoparticles can effectively supply vitamin D to cancer cells while also inhibiting cancer cell proliferation.