Antilymphocyte globulin (ALG), a polyclonal anti-human antibody directly against a number of T-cell antigens, using as an induction therapy in sensitized patients or as a second-line treatment of acute rejection in renal allograft recipients has side effects that can range from mild to life threatening. Although, adverse reactions to ALG may include fever, chills, dyspnea, tachycardia, malaise, thrombocytopenia, and leukopenia, but delayed onset of diffuse alveolar hemorrhage (DAH) should be considered as a rare and serious adverse event of ALG. At our institution, at least four patients have developed DAH with intravenous administration of ALG after kidney transplants. All cases except one cured by discontinuation of drug as well as respiratory supportive care. The delayed onset of respiratory complication also makes these rare cases intriguing. Even though all standard precautions for infusion of ALG were implemented, a presumably delayed life-threatening adverse reaction occurred. Premonitory subtle signs such as tachypnea, along with a high index of suspicion, may allow practitioners to predict those patients who may progress to serious cardiopulmonary compromise.