Background This study aimed to analyze and determine the incidence and mortality trends in gynecological and breast cancers (BCs) in Poland. The gynecological cancers assessed were cervical cancer (CC), corpus uteri cancer (CUC), ovarian cancer (OC), vaginal cancer (VAC), and vulvar cancer (VUC). Patients and Methods Data concerning the incidence and mortality for the period of 1980–2018 were obtained from the Polish National Cancer Registry (PNCR). Joinpoint regression analysis was performed to identify trends, which were described using the annual percentage change (APC) and the average annual percent change (AAPC). Results Statistically significant increases were observed in BC incidence (AAPC: 2.3; CI: 1.8 to 2.9; p<0.05), CUC incidence (AAPC: 2.3; CI: 1.9 to 2.7; p<0.05), CUC mortality (AAPC: 0.4; CI: 0.1 to 0.7; p<0.05) and VUC mortality (AAPC: 1.16, CI: 0.1 to 2.2; p<0.05). VAC mortality decreased (AAPC: −3.5, CI: −5.0 to –2.0; p<0.05), as did CC incidence and mortality (AAPC: −2.1, CI: −2.3 to −1.8; p<0.05, AAPC: −2.0, CI: −2.2 to –1.8; p<0.05, respectively). Between 1980 and 1993, OC incidence initially increased and then stabilized (AAPC: 0.9; CI: 0.7 to 1.1; p<0.05). After 2007, OC mortality decreased (AAPC: 0.0; CI: −0.2 to 0.2; p=0.8). Trends in VUC and VAC incidence and BC mortality were not statistically significant. Conclusion The results of this study showed a significant increase in OC, CUC, and BC incidence, and a decrease in the incidence of CC and VAC. The VUC trends were stable. Mortality trends for BC initially fluctuated and, since 2010, has begun to increase. Throughout the observed period, mortality due to VUC and CUC increased, whereas decreased among patients with CC. OC mortality was stable, but not significant. Furthermore, the study showed a correlation between age group and rate of incidence and mortality of each assessed cancer.