Background Pneumocystis jirovecii pneumonia (PJP) remains a cause of mortality in HIV-negative patients. The clinical benefit of adjuvant corticosteroids in these patients is uncertain. This study aimed to determine if corticosteroids reduced mortality in a cohort of HIV-negative PJP patients. Methods We examined a retrospective case series of patients diagnosed with PJP at the University of Colorado Hospital between 1995-2019. Data were collected in 71 PJP-infected patients. Twenty-eight patients were HIV-negative, and 43 were infected with HIV. We performed bivariate and forward, stepwise multivariable logistic regressions to identify mortality predictors. Results Common underlying conditions in HIV-negative patients were hematologic malignancies (28.6%), autoimmune disorders (25.9%), or solid organ transplantation (10.7%). HIV-negative patients had higher rates and duration of mechanical ventilation and ICU stay. Survival was significantly increased in HIV-negative patients receiving adjuvant corticosteroids, with 100% mortality in patients not receiving corticosteroids vs 60% mortality in patients receiving corticosteroids (p=0.034). In an adjusted multivariable model, no adjuvant corticosteroids use was associated with higher mortality (OR 13.5, 95% CI: 1.1-158.5, p= 0.039) regardless of HIV status. Conclusions We found substantial mortality among HIV-negative patients with PJP and adjuvant corticosteroid use was associated with decreased mortality. Response to corticosteroids is best established in HIV infected patients, but emerging reports suggest a similar beneficial response in PJP patients without HIV infection. Further prospective studies may establish a more definitive role of corticosteroid addition among HIV-negative patients with PJP.