This study aimed at investigating the growth inhibitory effect of probiotic Lactobacillus on Candida species isolated from oral thrush of AIDS-defining ill patients. Clinical isolates of Candida species were obtained from Dalhatu Araf Specialist Hospital Lafia, Nasarawa State. de Man Rogosa Sharpe agar was used as starter culture for the isolation of Lactobacilli. The diameters of the antimicrobial assay were recorded using the following dilution in part per mL (1:10, 1:100, 1:1000, 1:10000 and 1:100000) with the highest inhibition zone of 8 ± 1.414 mm followed by 7 ± 0.000 mm and the lowest dilution recorded as 5 ± 0.000 mm in the highest concentration of 1:10. As the dilution concentration decline, the inhibitions become weaker. The lowest dilution concentration (1:100000) however showed resistance in all the agar wells. Conclusively, Lactobacillus species has growth inhibition against yeast organisms in vitro. This study therefore recommends further research to identify more probiotic organisms that can potentially inhibit the growth of disease causing pathogens. Researchers should put more mental energy into use as research is the only source of solution to combat most of the emerging diseases around us.