Carboplatin-paclitaxel chemotherapy combination is the standard first-line treatment of advanced ovarian cancer and is the most commonly used treatment combination shown to be effective in advanced non-small-cell lung cancer (NSCLC). The most important dose-limiting side effect is hematologic toxicity. In this study, the severity of treatment-related myelotoxicity is compared in patients with advanced ovarian and lung cancers who received same schedule of carboplatin-paclitaxel. The study was prospectively performed from February 2009 to July 2011 and involved 103 patients with stages Ic-IV ovarian (n = 51) and advanced NSCLC (n = 52) who were administered a maximum of 6 cycles of carboplatin-paclitaxel as a first-line treatment. Full blood counts were measured before treatment, before each chemotherapy cycle during therapy, and at the first and sixth month after therapy. The median ages were 59 years (range, 35-77 years) for patients with NSCLC and 56 years (range, 38-75 years) for patients with ovarian cancer. The frequencies of anemia were 17% and 28.6% before the initiation of chemotherapy, 39.2% and 68.0% at the third cycle of treatment, and 44.2% and 45.2% at the sixth cycle of treatment in patients with NSCLC and ovarian cancer, respectively. Initial leukopenia rates were 3.4% and 0%; at the third cycle 46.0% and 41.2%; and at the sixth cycle 41.9% and 48.8% in patients with NSCLC and ovarian cancer, respectively. At the third cycle, 2.5% of the patients with NSCLC and 10.4% of the patients with ovarian cancer had thrombocytopenia, and at the sixth cycle, 23.3% of the patients with NSCLC and 25% of the patients with ovarian cancer had thrombocytopenia. Hemoglobin, leukocyte, and platelet values at the third cycle were significantly lower than those at admission in both cancer groups. Declines in hemoglobin levels in patients with NSCLC and in platelets in patients with ovarian cancer at the sixth cycle were statistically significant compared with the third cycle. In conclusion, the same schedule of chemotherapy may lead to different myelotoxicities in different types of cancer. These results should be taken into consideration in terms of supportive care and management of toxicity.