Background: There is paucity of knowledge on the proliferative features of normal or chronically inflamed gallbladder and the mechanisms of development of gallbladder cancer. Aim: To study the proliferation features of non tumoral gallbladder mucosa through the expression of Ki-67 antigen in tissue micro array analysis. Material and methods: The immunohystochemical expression of Ki-67 in tissue micro array was studied in 96 samples of non tumoral gallbladder mucosa (coming from 74 females aged 45±16 years and 22 males aged 53±16 years) and 102 samples of gallbladder cancer (coming from 84 females aged 62± 14 years and 18 males aged 70± 13 years). Results: The staining index of Ki-67 expression was 19±25% (range 096-8996) in samples of non tumoral mucosa and 46±29% (range 396-9896) in gallbladder cancer (p <0.01). Ki-67 was expressed in less than 10% of epithelial cells in 55% of non tumoral mucosa samples and 6% of gallbladder cancer samples. Seventy five percent of gallbladder cancer samples had a staining index of more than 20%. An expression of Ki-67 over 20% or 50% was observed in 25% and 15% of non tumoral mucosa samples, respectively Conclusions: Non tumoral gallbladder mucosa samples have a high proliferation index, measured using Ki-67 immunohystochemical expression. There is a group of samples with cellular hyper-proliferation that maybe related to the pathogenesis of gallbladder cancer.