Chemotherapy, a therapy commonly used by cancer patients, has a negative effect on blood cells in the bone marrow, which can result in Adverse Drug Reactions (ADRs) in the form of myelosuppression. This study aims to determine the incidence and severity of myelosuppression ADRs in post-chemotherapy patients with the Gemcitabine-Carboplatin regimen as well as the influencing risk factors. A total of 100 chemotherapy patients at RSUD Moewardi Surakarta in the period December 2023 – April 2024 were selected purposively to become research subjects. The research was conducted retrospectively using medical record data in the form of laboratory data including hemoglobin, platelet, leukocyte and neutrophil levels. Data were analyzed using the CTCAE instrument to determine the severity of ADRs and SPSS for univariate, bivariate and multivariate analysis. Myelosuppression in the form of anemia occurred in 92% of patients with grade 1 severity (59.80%); grade 2 (30.40%); grade 3 (8.70%); grade 4 (1.10%); thrombocytopenia in 31% of patients with grade 1 severity (58.10%); grade 2 (22.60%); grade 3 (16.10%); grade 4 (3.20%); leukopenia in 31% of patients with grade 1 severity (61.30%); grade 2 (25.80%); grade 3 (12.90%) and neutropenia in 17% of patients with severity grade 1 (100%). Risk factors that were significantly related to the incidence of myelosuppression were age (p = 0.000), number of cycles (p = 0.000 OR = 18.667), and comorbidities (p 0.010= OR = 3.195).