The purpose of this study is to determine factors predisposing to the infectious complications after renal transplant as well as the diagnostic and the therapeutics modalities in front of such a complication. It is a retrospective study of a 213 infectious complications case after renal transplant observed in the service of urology (Charles Nicolle Tunisia) between June 1986 and December 2005. Among our transplanted patients 146 (44 %) presented as urinary infection ( E.Coli 21,2 %, Enterobacter species 11 %, Pyocyanique 10 %, Pseudomonas 9,5 %, Klebsiella 9,5 %, Staph 9 %, Tbc 1 case). The infection was premature in 109 cases (74.6 %) and noted later in 37 patients (25.4 %). Among our patients 36 (11 %) presented as lung infection. In 13 cases (36 %) it was premature, 23 late (64 %). The causative agent was the BK in a case, staph in 3 cases, Pneumocystis carinii in 2 cases and no specific germ in the other cases. We listed 6 cases of meningitis among which one was due to Listéria and with 3 deaths. Among 213 patients 90 presented a viral infection (53 CMV, 32 herpes, 7 zona, 1 EBV) and 18 fungal infections to candida (8 oral, 10 cutaneous). In conclusion, the post renal transplant infection is a frequent complication and which can be grave.