Obtaining nanoscale materials has allowed for the miniaturization of components, which has led to the possibility of achieving more efficient devices with faster functions and much lower costs. While hydroxyapatite [HAp, Ca 10(PO 4) 6(OH) 2] is considered the most widely used material for medical applications in orthopedics, dentistry, and general surgery, the magnesium (Mg) is viewed as a promising biodegradable and biocompatible implant material. Furthermore, Mg is regarded as a strong candidate for developing medical implants due to its biocompatibility and antimicrobial properties against gram-positive and gram-negative bacteria. For this study, magnesium-doped hydroxyapatite (Ca 10−xMg x (PO 4) 6 (OH) 2, x Mg = 0.1), 10MgHAp, suspensions were successfully obtained by an adapted and simple chemical co-precipitation method. The information regarding the stability of the nanosized 10MgHAp particles suspension obtained by ζ-potential analysis were confirmed for the first time by a non-destructive ultrasound-based technique. Structural and morphological studies of synthesized 10MgHAp were conducted by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy in attenuated total reflectance (ATR) mode and scanning electron microscopy (SEM). The XRD analysis of the 10MgHAp samples confirmed that a single crystalline phase associated to HAp with an average grain size about 93.3 nm was obtained. The FTIR-ATR spectra revealed that the 10MgHAp sample presented broader IR bands with less visible peaks when compared to a well-crystallized pure HAp. The SEM results evidenced uniform MgHAp nanoparticles with spherical shape. The antimicrobial activity of the 10MgHAp suspension against gram-positive strains ( Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212), gram-negative strains ( Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853), as well as a fungal strain ( Candida albicans ATCC 90029) were evaluated.