Multiferroic composites with ferromagnetic and ferroelectric properties can be used in nanobiomedicine and multifunctional drug load owing to their strong magnetoelectric performance at room temperature. In this study, cobalt ferrite (CFO) and barium titanate (BTO) nanocomposites are synthesized by chemical co-precipitation method, the fraction of CFO with respect to the BTO is 20, 40, and 60 wt% (hereafter abbreviation as C20, C40, and C60). In this way, CFO as the growth site of BTO grains, forms a structure that BTO grains coated CFO grains. With the addition of CFO, the crystalline size of BTO in nanocomposites become smaller than pure BTO, particles size of nanocomposites is between 48 and 60 nm, lower than pure BTO. Smaller particle size of nanocomposites lead to higher dielectric constant in nanocomposites. The magnetization (M) versus field (H) loops reveal the ferromagnetic nature of CFO–BTO nanocomposites. All nanocomposite samples present outstanding ME effect with high α_ME value of exceeding 41 mV Oe⁻¹ all samples, reaching 44.13 mV Oe⁻¹ of C20.