The effects of simulated acid fog (SAF) and ozone (O 3 ) stress on the growth and physiology of beech (Fagus crenata) saplings were investigated. Three-year-old beech saplings were exposed to SAFs of pH 3 and pH 5 (control) during May 2007 to July 2008. In each SAF treatment group, half of the saplings were exposed to 60 ppb of O 3 during September 2007 to July 2008. In comparison to the control saplings, those from the pH 3 treatment had lower total plant biomasses, epicuticular wax amounts, Ca 2? concentrations in their leaves, and lower starch concentrations in their leaves and roots. The effect of O 3 was significant only for the starch concentration in the roots, but the O 3 exposure also negatively affected the growth and physiology of beech saplings. Results show that acid fog exerts various severe effects, and that both chronic acid fog and O 3 exposure suppressed the physiological functions of beech saplings.