Background: Prostate cancer (PCa) diagnosis is not uncommon in younger men. The three recognized risk factors for PCa are increasing age, african-american race and a family history (FH). Data about PCa treatment outcomes are controversial, younger men may have more aggressive disease and worse prognosis. On the other hand, more recent studies suggest higher rates of indolent PCa with more favorable outcomes in young men after radical prostatectomy (RP). We aimed to compare younger (G1, ≤ 55 yo) vs. older adults (G2, > 56 yo) who underwent RP for PCa between 2010-2016 in terms of FH, race and tumor aggressiveness. Secondly, to determine if the PCa in G1 is more aggressive when there is a PCa familiar background. Methods: Between 2010-2016, 419 men underwent RP for clinically localized PCa at Central Lisbon Hospitals, of which 49 were aged ≤55 years at the time of RP. Clinical characteristics such as race, FH, PSA level, clinical stage, and biopsy Gleason score (BGS) were recorded before RP. Pathological parameters (pathological stage, GS and PSA) were collected after surgery. Results: In G1, 31% had PCa FH vs. 10% in G2 (p < 0.001). Before RP, the average PSA in G1 was 7.47 vs. 8.08 in G2 (p = 0.371). In BGS, 44,3% had Gleason (G) 6, 37,4% G7, 6.9% G≥8, not significantly different between both groups (p = 0.651). Albeit, G1 had more aggressive tumors after RP: 27% G6, 45% G7 e 29% G≥8 vs. 37%, 53% e 11% respectively in G2 (p = 0.002). The pathological stage (pT) was not significantly different between groups (p = 0.243). Biochemical recurrence (BCR) was higher in G1 20% vs. 9% (p = 0.010). In a multivariate logistic regression model, the G1 had more BCR (p = 0.047) and higher PCa FH incidence (p = 0.002). When comparing african vs. caucasian men, the first group had more aggressive tumor histology (p = 0.021). Conclusions: Our study demonstrated that the youngest had superior pathological grades with higher BCR rates. Also, we found a strong relationship between G1 and FH of PCa. Data regarding pathological findings after RP in young men are still controversial. Recent studies confirm that pathological PCa characteristics in young men are not more aggressive than in older men. The present intends to add to the scientific debate around the impact of patients’ age in PCa aggressiveness and prognosis.