The aim of this study was to examine the effect of different periods of fermentation of chicken litter on in vitro volatile fatty acids (VFA) and ammonia (NH3) concentrations. This study used a completely randomized design (CRD) with 4 treatments and 4 replications. The treatments tested were T0 = fermentation 0 weeks, T1 = fermentation 3 weeks, T2 = fermentation 6 weeks and T3 = fermentation 9 weeks. The parameters observed in the study were the concentration of VFA and NH3 fermentation litter. The results showed that the concentration of VFA and NH3 was not significantly affected by the length of ripening, with the average value concentration of VFA total fermented litter ranging from 70 – 85 mM while the concentration of NH3 in the fermented litter was 18,84 – 23,28 mg/100 ml. The conclusion of the study was that different fermentation times did not affect the concentration of total VFA and NH3 concentrations.