Febrile neutropenia (FN) is a critical complication of chemotherapy associated with increased in-hospital mortality. However, associations with increased mortality and intensive care unit (ICU) admissions during longer follow-up are not established. Patients treated with standard first-line chemotherapy for solid cancers at Rigshospitalet, Denmark in 2010-2016 were included. Incidence rate ratios (IRR) of all-cause, infectious and cardiovascular mortality, and ICU admissions after FN were analyzed by Poisson regression. Risk factors at the time of FN were analyzed in the subpopulation of patients with FN; all-cause mortality was further stratified by the time periods 0-30, 31-365, and 366+ days after FN. We included 9018 patients with gastric (14.4%) and breast (13.1%) cancer being the most common, 51.2% had locally advanced or disseminated disease and the patients had a median Charlson Comorbidity Index score of 0 (interquartile range, 0-0). During follow-up, 845 (9.4%) experienced FN and 4483 (49.7%) died during 18 775 person-years of follow-up. After adjustment, FN was associated with increased risk of all-cause mortality, infectious mortality, and ICU admissions with IRRs of 1.39 (95% CI, 1.24-1.56), 1.94 (95% CI, 1.43-2.62), and 2.28 (95% CI, 1.60-3.24). Among those with FN, having a positive blood culture and low lymphocytes were associated with excess risk of death and ICU admissions (predominantly the first 30 days after FN), while elevated C-reactive protein and low hemoglobin predicted mortality the first year after FN. The risk of death varied according to the time since FN; adjusted IRR per additional risk factor present for the time periods 0-30, 31-365, and 366+ days after FN were 2.00 (95% CI, 1.45-2.75), 1.36 (95% CI, 1.17-1.57), and 1.17 (95% CI, 0.98-1.41). FN was associated with increased mortality and risk of ICU admissions. An objectively identifiable subgroup of patients among those with FN carried this excess risk.