The adaptability of cacao (Theobroma cacao L.) to adverse conditions, suggests that the microbiota associated with the rhizosphere of this plant could play an important nutrition and development function. In this paper was valuated the potential of biofertilizer nitrogen fixing bacteria (diazotrophas) isolated by the technique of serial dilutions of cacao soils. Bacteria were isolated on semiselective media (NFb,JMV, LGI, JNFb). The pure isolates were characterized morphologically and biochemically and, additionally the capacity of biological nitrogen fixation (BNF) was evaluated by the Micro-Kjeldahl method. Isolates with better nitrogen fixation ability were selected to evaluate their potential for growth promoter in cocoa plants from seed CCN 51 for 120 days with a control without inoculum. As a result of statistical analysis, the cocoa plants effectively responded to bacterial treatments where growth variables and foliar % N, were significantly increased compared with the control whose response was lower. Highlighting the contribution of isolated DKA2J24 and DKB3J73 presumably genus Burkholderia sp., and DKA1L3 like genus Gluconacetobacter sp. all with great potential as biofertilizers in the bioassay test.