We conducted a daily analysis of bile cellularity in 16 orthotopic liver transplant patients fitted with a T-tube, and correlated the cytological parameters (number of cells per slide, and percentage of difference cell types) with the duration of cold ischemia time (CIT). Two groups were established: one comprised patients whose CIT was less than 7 hr (CIT averaged 345 min) and the other comprised patients with a CIT of more than 7 hr (CIT averaged 505 min). The control group consisted of 15 patients who had received cholecystectomy for biliary lithiasis and were fitted with a T-tube. All 3 groups showed the highest cell density on the 1st postoperative day (control: 53.3 +/- 15.5 cells/slide; short ischemia: 70 +/0 21.4 cells/slide; long ischemia: 158.8 +/- 53.2 cells/slide), which steadily ischemia group showed a higher cell density than did the control group for the first 2 days, although this was not significant. The long ischemia group showed the highest cell density, although only significantly for the first 2 days when compared with the controls, and basically at the expense of a increase in ductal epithelial cells. Our results show that prolonged cold ischemia causes an increase in bile cell density at the expense of ductal epithelial cells: the longer the preservation time, the greater the increase.