Survival and growth of pearl oyster, Pinctada mazatlanica, juveniles fed microalgae supplemented with natural and commercial probiotics were measured for 21 d at the hatchery. Probiotics tested were (1) a Lactobacillus sp., (2) a mix of two bacilli, Burkholderia cepacia and Pseudomonas aeruginosa, (3) a marine yeast, Yarrowia lipolytica, (4) Epicin-hatchery® as commercial probiotic, (5) an antibiotic oxytetracycline, and (6) the control group fed Isochrysis galbana, Pavlova salina, and Chaetoceros muelleri only. When the hatchery phase ended, the effects of probiotics were followed during the early stages of field cultivation (90 d). Different from the control group, natural probiotics significantly improved performance of juveniles during both phases, particularly in the field. The treatment with Lactobacillus sp. significantly increased survival by 72%, growth in shell height by 63%, and growth in wet weight by 83% over the control. The marine yeast and mix of bacilli provided intermediate results, enhancing survival by 55-65%, shell height by 55-58%, and wet weight by 70-76% compared with the control. Conversely, growth and survival in the treatments with Epicin and oxytetracycline were significantly lower than in the control. These results show the potential of natural probiotics for improving hatchery rearing of this pearl oyster.