This post-marketing surveillance (PMS) study is designed to investigate the efficacy and safety of azathioprine tablets in Japanese subjects whom liver transplantation is performed.

Inclusion Criteria:

• Subjects who undergo liver transplantation and azathioprine tablet was administered

Exclusion Criteria:

As this is PMS study, there are no exclusion criteria but contraindications are as follows.

• Subjects with hypersensitivity to the ingredients of azathioprine tablet
• Subjects who is pregnant or might be pregnant
• Subjects whose white count is lower than 3000/cubic millimeter

The following subjects to whom azathioprine tablet is administered for "the suppression of liver transplant rejection";

• Subjects on whom liver transplantation is performed and to whom azathioprine tablet is administered within 1 year after transplant surgery from the approval date of the additional indication of azathioprine tablet for liver transplantation (20 June 2001) to May 2010.
• Subjects on whom liver transplantation is performed before the approval date of the additional indication of azathioprine tablet for liver transplantation (20 June 2001) and to whom azathioprine tablet is administered within 1 year after transplant surgery.