Magnetosomes are nanosized iron oxide particles surrounded by lipid membrane synthesized by magnetotactic bacteria (MTB). Magnetosomes have been exploited for a broad range of biomedical and biotechnological applications. Due to their enormous potential in the biomedical field, its safety assessment is necessary. Detailed research on the toxicity of the magnetosomes was not studied so far. This study focuses on the toxicity assessment of magnetosomes in various models such as Human RBC’s, WBC’s, mouse macrophage cell line (J774), Onion root tip and fish (Oreochromis mossambicus). The toxicity in RBC models revealed that the RBC’s are unaltered up to a concentration of 150 µg/ml, and its morphology was not affected. The genotoxicity studies on WBC’s showed that there were no detectable chromosomal aberrations up to a concentration of 100 µg/ml. Similarly, there were no detectable morphological changes observed on the magnetosome-treated J774 cells, and the viability of the cells was above 90% at all the tested concentrations. Furthermore, the magnetosomes are not toxic to the fish (O. mossambicus), as no mortality or behavioural changes were observed in the magnetosome-treated groups. Histopathological analysis of the same reveals no damage in the muscle and gill sections. Overall, the results suggest that the magnetosomes are safe at lower concentration and does not pose any potential risk to the ecosystem.