Cardiac resynchronization therapy (CRT) is effective in heart failure with reduced ejection fraction (HFrEF) and dyssynchrony but isunderutilized. In a cohort study, we identified clinical, organizational, and level of care factors linked to CRT implantation. We included HFrEF patients fulfilling study criteria in the ESC-HF-Long Term Registry (ESC-HF-LT, n=1031), the Swedish Heart Failure Registry (SwedeHF) (n=5008), and the ESC-CRT Survey II (n=11088). In ESC-HF-LT, 36% had a CRT indication of which 47% had CRT, 53% had indication but no CRT, and the remaining 54% had no indication and no CRT. In SwedeHF, these percentages were 30, 25, 75, and 70%. Median age of patients with CRT indication and CRT present vs. absent was 68 vs. 65 years with 24% vs. 22% women in ESC-HF-LT, 76 vs. 74 years with 26% vs. 26% women in SwedeHF, and 70 years with 24% women in CRT Survey II (all had CRT). For ESC-HF-LT, independent predictors of having CRT were guideline-directed medical therapy (GDMT), atrial fibrillation (AF), prior HF hospitalization, and NYHA class. For SwedeHF, they were GDMT, age, AF, previous myocardial infarction, lower NYHA class, enrolment at university hospital, and follow-up at HF centre/Hospital. In SwedeHF, above median income and higher education level were also independently associated with having CRT. In the ESC-CRT Survey II (n=11088), all patients received CRT but with differences in the clinical characteristics between countries. CRT was used in a minority of eligible patients and more used in ESC-HF-LT than in SwedeHF.