Pneumonia caused by Pneumocystis jirovecii is an uncommon infection in kidney transplant patients that can have an acute and rapid progression to respiratory failure and death. The period of greatest risk occurs in the first six months after the transplant, and it relates to the high doses of immunosuppression drugs required by patients. However, it may occur late, associated with the suspension of prophylaxis with trimethoprim-sulfamethoxazole.We present two cases of renal transplant patients who had severe hypoxemic respiratory failure due to P. jirovecii six years after transplantation. In addition to steroids, they received treatment with trimethoprim-sulfamethoxazole. One patient died, while the other had clinical recovery, with preservation of the renal graft function.