Timely diagnosis is one of the most serious challenges faced by people living with a rare disease (PLWRD), and this new research estimates that in Europe, the average Total Diagnosis Time (TDT) is 4 to 5 years. We investigated the duration of the TDT for PLWRD in Europe, the difficulties associated with their diagnosis odyssey and the main determinants of diagnosis delays for all rare diseases (RD). We conducted a survey of PLWRD and their families between March and June 2022 using Rare Barometer, the survey initiative of EURORDIS-Rare Diseases Europe. In geographical Europe, we surveyed 6,507 people living with 1,675 RD in 41 countries. We then peformed a descriptive analysis and ordinal logistic regressions to identify the main determinants of diagnosis delays. Average TDT is 4.7 years. 56% of respondents were diagnosed more than 6 months after a first medical contact. The main determinants of diagnosis delays are symptom onset before 30 years of age, especially during childhood (OR = 3.11; 95% CI: 2.4-4.0) and adolescence (OR = 4.79; 95% CI: 3.7–6.2), being a woman (OR = 1.22; 95% CI:1.1–1.4), living in Northern Europe (OR = 2.15; 95% CI:1.8–2.6) or Western Europe (OR = 1.96; 95% CI:1.6–2.3), the number of healthcare professionals consulted (OR = 5.15; 95% CI:4.1–6.4), misdiagnosis (OR = 2.48; 95% CI:2.1–2.9), referral to a centre of expertise (OR = 1.17; 95% CI:1.0-1.3), unmet needs for psychological support (OR = 1.34; 95% CI:1.2–1.5) and financial support (OR = 1.16; 95% CI:1.0-1.3), having a genetic disease (OR = 1.33; 95% CI:1.1–1.5) and a family history of a RD (OR = 1.36; 95% CI:1.1–1.6). These determinants can inform policies and actions to improve access to diagnosis for all PLWRD.