Volatile fatty acids (VFAs) have gained a very extensive research interest since they are important building blocks for the chemical industry. This acids can be produced via anaerobic digestion (AD) which have shown to be an environmental friendly process since it utilizes waste products such as sludge and food waste as substrate. Anaerobic digestion can occur naturally and produces biogas as main product. VFAs are intermediary products formed during the anaerobic degradation process. The main objective of this study was to investigate how to optimize the degradation process aiming to produce a high amount of VFAs instead of producing biogas. Operation parameters, such as pH and time during anaerobic degradation of sludge and/or food waste in mesophilic conditions were examined. The highest VFA concentrations observed was 15.4 g/L when using sludge as substrate with a yield of 0.77 gVFA/gVS at day 14. For food waste, as substrate, the highest concentrations observed was 9.7 g/L with a yield of 0.49 gVFA/gVS at day 13, while the digestion of a mix of food waste and sludge resulted in 10.92 g/L VFAs production with a yield of 0.55 gVFA/gVS at day 13.