The present study was proposed to evaluate the potential use of potato- chips waste as a substrate for citric acid production by solid-state fermentation. Potato- chips waste could serve as a substrate for citric acid production. Maximum amount of citric acid (23.19g/100g) was produced by Aspergillus niger when it was cultivated on the optimized waste medium for 7 days at 30°C. The waste was prepared as follows: it was milled to 1.0-1.5mm, cooked at 121°C for 2hr,adjusted to moisture level of 65% v/w, with pH 3.5 and enriched with 0.0125% w/w nitrogen in form of ammonium nitrate and 4% v/w of methanol was added