Despite increasing clinical recognition of atrial functional tricuspid regurgitation (AF-TR), there remains limited literature regarding the characteristics, outcomes, and adverse prognosticators for this valve lesion.This study aimed to elucidate clinical and echocardiographic characteristics and outcomes and to develop a novel risk model in a large cohort of patients with significant AF-TR.Consecutive patients with at least moderate-to-severe AF-TR seen between January 2004 and December 2018 were retrospectively studied. Univariable and multivariable logistic regression (OR) were conducted to determine the risk factors and develop novel risk scores for 1-year all-cause mortality.Among 370 patients with AF-TR (mean age 73.9 ± 15.0 years, 82.2% female; mean follow-up 4.1 ± 3.6 years), 1-year and total mortality occurred in 81 (21.9%) and 219 (59.2%) of patients respectively, with a median survival of 2.5 and 8.5 years for patients with AF-TR effective regurgitant orifice area ≥0.40 and <0.40 cm2. Multivariable analyses identified right heart failure (OR: 2.40; 95% CI: 1.31-4.41), lower serum albumin (OR: 0.88; 95% CI: 0.85-0.92), higher right atrial volume indexed (OR: 1.25; 95% CI: 1.04-1.49), lower tricuspid annular plane systolic excursion/right ventricular systolic pressure ratio (OR: 0.82; 95% CI: 0.70-0.95), and higher TR-effective regurgitant orifice area (OR: 1.11; 95% CI: 1.02-1.21) to be independently associated with 1-year mortality, from which a risk model was derived with good discrimination (area under the curve: 0.87).Patients with AF-TR had poor prognosis especially if tricuspid regurgitation effective regurgitant orifice area was ≥0.40 cm2, validating the guidelines threshold for severe tricuspid regurgitation. A novel risk score for 1-year mortality in patients with AF-TR was developed, offering potential utility for risk stratification and treatment guidance; however, external validation is needed.