There is limited proof in regards to the dangers of incident atrial fibrillation (AF) related to stage-1 isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systolic-diastolic hypertension (SDH), particularly among youthful grown-ups. We expected to assess the relationship between the beginning phase of high blood pressure and atrial fibrillation in youthful grown-ups. From the Korean cross country health screening information base, 2,958,544 subjects [age range (in years): 20 to 39] who were not recommended antihypertensive medicine at the index examination in 2009 were incorporated. The 2017 American College of Cardiology/American Heart Association blood pressure (BP) guidelines allowed us to classify the subjects into eight distinct categories. Those are – normal BP, raised BP, stage 1 IDH, stage 1 ISH, stage 1 SDH, stage 2 IDH, stage 2 ISH, and stage 2 SDH. The essential result was new-onset AF. 7347 individuals had incident AF (0.3 per 1000 person-years) as demonstrated by a median follow-up of 8.3 years. In comparison to normal BP, stage 1 IDH (adjusted danger proportion, 1.160 [95% CI, 1.086–1.240]) and stage 1 SDH (1.250 [1.165–1.341]) were related with higher dangers of incident AF, but not stage 1 ISH. Stage 2 IDH, ISH, and SDH were related to higher dangers of incident AF by 24%, 37%, and 61%, respectively. Stage 1 IDH and SDH were related to higher dangers of incident AF in comparison to normal BP. The danger of incident AF with stage 2 IDH was like that of stage 1 SDH. Including diastolic BP, optimal BP control is related to the most minimal danger of new-set AF, even among youthful grown-ups.