Storage of Norgold and Russet Burbank tubers at 3°C in air led to accumulation of sucrose and hexose and a decline in chip color quality to unacceptable levels (Hunter L values less than 40) within 2 wk. Storage in modified atmospheres of 1000 ppm ethylene in air and low oxygen delayed decline in color by 6-8 wk compared with storage in air. Storage in 1000 ppm ethylene apparently reduced rate of conversion of sucrose to hexose. The low oxygen atmosphere appeared to reduce extent of sucrose accumulation and rate of sucrose conversion to hexose during storage.