Fine Co-Ti substituted barium ferrite particles (500 to 1000 ??) with high dispersibility and highly uniform size were fabricated by a hydrothermal synthetic method accompanied by heat treatment, and their magnetic properties were studied. Sample characterization relied on X-ray diffraction, M??ssbauer spectra obtained with a 16.4 kOe field applied parallel to the incident ??-rays showed the formation of a plane of easy magnetization in Co-Ti substituted barium ferrite, which may be the origin of an abrupt magnetic softening of this system even at low substitution levels. An increased saturation magnetization was obtained by lowering the Ti content from the equimolecular ratio with Co ions.