Use of nanoparticles as carriers of anticancer drugs is a suitable way for targeted drug delivery and reduction of the side effects. This research focuses on a novel drug carrier for therapeutic goals by the bacterial magnetic nanoparticles (magnetosomes). The unique characteristics of magnetosomes make them ideal nanobiotechnological materials. In this study, magnetic nanoparticles of Alphaproteobacterium MTB-KTN90 were labeled with the radioisotope rhenium-188 and optimized the factors affecting the labeling efficiency. The results showed that the labeling efficiency of magnetosomes with rhenium-188 was more than 96%. The optimum concentration of bacterial nanoparticles was 133 mg/ml and the best time for maximum efficiency labeling was 60 min. The labeling stability showed that the Re-188-nanoparticle complexes have good stability in 29 h. The results of magnetic nanoparticles bacterial cytotoxicity on cancer cells AsPC1 did not show significant toxicity to concentration of 100 mu g/mu l. Finally, the biogenic magnetic nanoparticles labeled with rhenium-188 can be introduced as a valuable candidate for the targeted therapy of tumor with reducing radiation to surrounding healthy tissues.