The impact of antifungal therapy on economic outcomes in patients with invasive aspergillosis (IA) needs further exploration. The purpose of this study was to describe antifungal therapy and factors associated with hospital length of stay (LOS) in transplant patients with IA. Patients were enrolled from March 2001 to October 2005 and IA cases identified through March 2006 from a sub-group of patients in the Transplant Associated Infection Surveillance Network (TRANSNET). Factors associated with hospital LOS were determined by logistic regression analysis. Of 361 patients, the mean age was 49 years, 60.7% were male, and 63% were hematopoietic stem cell transplantation (HSCT) recipients. Primary monotherapy was used in 233 (64.5%) patients, of which voriconazole (93/233, 39.9%) was most commonly used antifungal. Primary combination therapy was used in 128 (35.4%) of 361 patients, with voriconazole plus caspofungin (81/361, 22.4%) the most frequently employed. Mean duration of therapy was 115 days (HSCT 109.7; solid organ transplant [SOT] 125.3). Mean hospital LOS was 35.3 days (HSCT 38.7; SOT 29.7). Regression analysis identified disseminated IA, neutropenia, malnutrition and length of ICU stay as factors associated with increased hospital LOS. Initial voriconazole use was associated with decreased LOS. Further investigation on impact of antifungal therapy on economic outcomes is needed. © 2013 ISHAM.