In this work, a comparison between Impedance Spectroscopy (IS) and Plate Counting to probe the growth of Lactobacillus acidophilus (La) was done. It was found that after inoculation, and after 0.8 h, the microbial growth was noticed by IS, inferred by the λ parameter. In contrast, by means of the Plate Counting method, the growth was noticed after 6.8 h. The experimental data obtained by IS were first fitted by an RC series circuit, and then, the curves generated were modeled by the well-known growing models of Gompertz and Boltzmann. When using the IS technique, it was found that the resistance of the medium was a better parameter to describe the growing process of La.