The effects of compost and liquid biofertiliser on the chemical and biological characteristics of soil cultivated with banana (Musa spp. L.) cv. 'Grand Naine' were investigated. Four treatments (liquid bioferment (LBF), compost (COM), liquid bioferment + compost (LBF + COM) and unamended (CONTROL)) were applied to banana plants in the field in a completely randomised design in the crop cycles of 2005-2006 and 2007-2008. The physico-chemical characteristics, enzymatic activity and microbial diversity were determined prior to the bioferment addition and 140 and 280 days after application (DAP). The microbial groups were determined (i.e., bacteria, fungi, actinomycetes). Next, cellulolytic, proteolytic, starch hydrolysing, asymbiotic N2-fixing and phosphorous-solubilising microorganisms were determined. The application of LBF + COM increased organic matter 1.39 times, increased compost 1.33 times and increased LBF 1.16 times at 140 DAP. The greatest microbial populations were found in soil amended with LBF + COM at 140 DAP. The highest esterase and invertase enzyme activities were found in soil amended with LBF+COM at 140 DAP. The highest xylanase activity was found in soil amended with compost at 280 DAP. These results showed that the addition of compost and liquid bioferment improves soil fertility and stimulates microbial activity and their capacity to metabolise complex organic molecules.