Cocoa powder is made from fermented cocoa beans which are separated from fat, grounded and sifted to produce a powder. The fermentation stage is an important stage in processing cocoa beans for chocolate flavor formation. The traditional fermentation done by farmer triggers fungal growth that can produce a toxin called mycotoxin. The use of lactic acid bacteria in cocoa beans fermentation has been known to inhibit the growth of mycotoxin-producing fungi. The addition of Lactobacillus plantarum HL 15 as a culture starter has known as an antifungal. The objective of this research is to study the effect of Lactobacillus plantarum HL 15 as culture starter and fermentation box variation on microbiology, chemical and sensory characteristics of cocoa powder. Cocoa beans fermentation was conducted by starter culture addition and without starter culture addition and then using a new fermentation box and old fermentation box. The analysis of cocoa powder was carried out include water content, pH, fungi contamination, and sensory evaluation on color, flavor and taste of the cocoa powder. The result showed that water content (3.85 % to 4.55%), pH (4.85 to 4.95), and sensory evaluation is not significant differences for all treatment. The addition of Lactobacillus plantarum HL 15 as a culture starter in old and new fermentation boxes has a smaller lever of fungi contamination compare to the treatment without Lactobacillus plantarum HL 15 as culture starter.