Introduction: Penicillin is an antibiotic that has been mostly found and used in daily life. Penicillin is produced by the carbohydrate fermentation of Penicillium chrysogenum grown on the medium of nutrient agar or broth. In addition, P. chrysogenum can also be grown over a natural medium such as the enriched tomato juice. The tomato juice serves as the source of carbon, protein, and nutrition that the P. chrysogenum needs in performing the fermentation process. Regarding the statement, the growth of P. chrysogenum over the tomato juice as the medium can be studied through the biomass parameter, reducing the sugar through the Nelson-Somogyi method, and the penicillin activities resulted by the obstacle zone test. Methods: The tools that had been used in the study were test tube, LAF, oven, Petri dish, autoclave, spectrophotometer, vortex, pH meter microwave, incubator shaker, and water bath. Results: Then, based on the results of the study that has been conducted, it is found that the improvement of the biomass and the presence of the reduced sugar in the medium have shown the growth phase of P. chrysogenum. Conclusion: The penicillin growth and activities found in Penicillium chrysogenum grown over the tomato juice as the medium has indicated the presence of the growth phase.