Background & aim: There are so many studies about effect of colored drinks and mouthwashes on discoloration of different dental ceramics. However, little is known regarding the effect of colored drinks on discoloration of monolithic zirconia .The purpose of this invitro study was to evaluate the effect of different surface treament methods on color stability of monolithic zirconia. Material and methods:: this experimental study was conducted in vitro on monolithic zirconia ceramics. Twelve pre-tinted specimens of monolithic blocks (1.5 mm, 14 ,14 mm) were prepared and divided into 2 groups (A) glazed and (B) polished after glaze .Specimens were sintered and glazed and Specimens of group B were prepared and polished. The specimens were placed in Golestan bag teas (ph = 5) for two weeks and color of the specimens were measured using spectrophotometer before and after immersion. the color changes (ΔE) were determined by Mann-Whitney test.Results: This study showed color change rate in the polish group was 3.2 ± 0.1 and in the glaze group was 1.07 ± 1.1, p˂0.7, and the color change in the polish method was about 2 times more that of glaze method which is significant (p<0/004). Conclusions:Glaze Group seems to have less color change compared to polish group.