Infections after kidney transplantation,especially TB increase mortality and morbidity. The aim of this study is evaluation of prevalence of TB after kidney transplantation in Ghaem hospital of Mashad (IRAN). In a prospective study 508 patients from 1986 to 2003 were included for evaluation of TB after kidney transplantation. In the fever or pulmonary symptoms and etc... complete investigation including sputum smear, chest x ray and etc...were performed.Then relation between sex, age, kind of dialysis and time of diagnosis of TB were investigated. From 508 patients 58 patients (11.4%) before operation had positive PPD test (more than 10 mm) and from these patients only 1 patients developed TB and in 450 patients with negative PPD test 8 patients (1.77%) developed TB which had no significant relation (p>.05). 432 patients (85%) were on HD and 76 patients (15%) were on PD and all of our TB cases were seen in HD patients. 9 patients developed TB after transplantation (1.75%) which in 5 cases were in pulmonary and in 2 cases in pleural cavity and in 1 case in in lymph node and in 1 case in in native kidney. 55% of TB cases were seen in first year of transplantation and 33% in second year. In 33% of TB cases befor TB presentation we had episodes of acute rejection and in other hand 22% of TB cases after beginning of anti-TB treatment had rejection episodes. 1 patient died because of severity of pulmonary disease with no response to treatment. TB after transplantation increase mortality and morbidity.