A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Bone marrow transplants (BMT, also hematopoietic stem cell transplants or HSCT/SCT) are one of the greatest medical achievements of the 20th century. They offer a treatment for a host of malignant and nonmalignant hematopoietic disorders, genetic diseases and solid tumors that could otherwise be fatal. Studies have found that 60% of patients undergoing BMT develop pulmonary complications (PC), and 1/3 of those require intensive care after transplantation. Despite the potential pneumotoxicity of induction agents, to date there have been no longitudinal studies following pulmonary function in this high‐risk patient population. This study reviewed patient who underwent autogeneic bone marrow transplant for multiple myeloma at Banner University Medical Center – Tucson (formerly University of Arizona Health Network) from January 1, 2003 through December 31, 2013. Pretransplant evaluatin and pulmonary function testing data were obtained and stratified between high dose (standard) Melphalan (200 mg/ms2) and reduced dose (140 mg/ms2). Statistically significant differences were present between the 2 groups at baseline for DLCO but disappeared at 6 and 12‐month followup, while a statistically significant difference for FEV1/FVC ratio was seen at baseline and 6 months but disappeared at 12‐month follow‐up. There were no statistically significant differences seen with FEV1 between the two groups. Given there is no difference in mortality and relapse outcomes between the groups, the standard of care dosing for Melphalan is not associated with an increase in pulmonary morbidity.