Introduction: Invasive pulmonary aspergillosis (IPA) is a potentially lethal opportunistic infection. Old age is one of the important risk factors of IPA. However, data regarding the clinical characteristics and prognostic factors of elderly patients with IPA are limited, with data regarding co-infection of other bacteria or fungi even scarcer. Methods: We performed a retrospective study of elderly patients (aged≥60) with IPA diagnosed in the First Affiliated Hospital of Sun Yat-sen University from January 2000 to December 2019. Data collection included demographic characteristics, premorbid conditions, underlying diseases, clinical manifestations, therapeutic procedures, and pathogenic detection. Associated factors were analyzed by logistic regression analysis. Results: A total of 97 elderly patients (75 males, 22 females) with IPA were included. The all-cause mortality rate was 36.1% (35/97). Body mass index (BMI) (adjusted odds ratio (OR) 1.27, 95% confidence interval (CI) 1.08-1.50, P=0.01), solid organ malignancy (adjusted OR 5.37, 95% CI 1.35-21.33, P=0.02), and co-infections (adjusted OR 5.73, 95% CI 1.40-23.51, P=0.02) were associated with mortality in the elderly patients with IPA. Nearly, 76.3% (74/97) of the patients developed co-infections. Most of the infections (55/74, 74.3%) involved the lung. A total of 77 strains of bacteria were isolated, and Gramnegative bacteria (63/77, 81.3%) were predominant. Patients with co-infections are older (72.3±7.6 vs 67.4±7.4, P=0.04), prone to admit to the intensive care unit (ICU) (59.5% vs 26.1%, P=0.01), and present lymphopenia (60.8% vs 26.1%, P=0.004). In multivariate analysis, ICU admission (adjusted OR 4.57, 95% CI 1.53-13.67, P=0.01), and lymphopenia (adjusted OR 4.82, 95% CI 1.62-14.38, P=0.01) were significantly associated with coinfection in the elderly patients with IPA. Conclusion: IPA is a fatal disease in the elderly population. Co-infection is closely associated with mortality. Lymphopenia could be an indicator for co-infection in the elderly patients with IPA.