Postoperative pain is always not well controlled by current analgesics. Green tea is supposed to have analgesic and relaxing effect. This study assessed the effect of green tea on post-operative pain and anxiety in tibia surgery. A randomized double blind controlled trial has been conducted from May to September 2015in the north of Iran after being registered in Iranian Registry of Clinical Trials. Sixty eligible patients have randomly been assigned to either green tea (G) or placebo (P) group in quadripartite blocks. Pain severity and anxiety based on visual analogue scale (VAS)and State Trait Anxiety Inventory (STAI)were measured and compared two hours before surgery and drink intake (T0), after recovery filling Aldrete criteria(T1) and eight hours after the end of surgery (T2).Statistical analysis was performed by Chi-square test and repeated measurement in SPSS version 20. In the group of G and P 36 and 32patients remained with mean age of 36.76±10.96 and 41.26±11.44 years (p=0.120). Respectively 69.4% (n=25) and 75% (n=24) of participants were menin groups (p=0.787) and the mean of Body Mass Index (BMI) was 27.81±3.88 and 28.27±5.37 (p=0.706). There was no significant difference in VAS score in each group and also between two groups in three measurement point times. The difference of STAI was significant in each group (p=0.001) and between two groups (p=0.01) in three measurement point times. Green tea could diminish postoperative anxiety but not post-operative pain.