Medical records for 67 cats with histologically confirmed mammary gland adenocarcinomas treated with adjunctive doxorubicin from June 1994 through December 2002 were reviewed. Data were examined to evaluate factors influencing disease-free interval (DFI) and survival time. The Kaplan-Meier median survival time of cats that received surgery and doxorubicin was 448 days. The Kaplan-Meier median DFI was 255 days. Significant univariate prognostic factors for DFI included histological subtype, completion of initial chemotherapy, development of metastatic disease, and location of metastatic disease. Significant univariate prognostic factors for survival included tumor volume, the development of metastatic disease, and location of metastatic disease.