Calcium phosphate (CaP) ceramics have been prevalently used as coatings for implants because of their excellent osteoconductive and bioactive properties. Yet, bone regeneration procedures might have complications such as bacterial infection, local inflammation, bone destruction, and impaired bone healing. Here, we present a novel in situ electrodeposition of CaP with chitosan nanoparticles containing antibiotics. The deposition was shown to be fast and efficient. The deposited layer of octacalcium phosphate (OCP) and monotite contained a large amount of gentamicin, which was released gradually over a period of 15 days. These phases may be beneficial for bone growth, as OCP has higher solubility than the stoichiometric hydroxyapatite (HAp) and is commonly considered as a precursor to HAp, while monotite has even faster resorbability. In addition, both the cytotoxicity and biomineralization of the coating were studied, and the coating was proven to be noncytotoxic and highly biomimetic.