Background: Circulating tumor DNA in plasma (ctDNA) is an emerging resource for detecting genomic alterations in various cancers. However, the characteristics and clinical utility of ctDNA are not fully elucidated, especially in patients with genitourinary (GU) cancers. Methods: In April 2019, SCRUM-Japan started the MONSTAR-SCREEN project, which evaluates the ctDNA from patients with various advanced solid tumors. We collected plasma and tumor samples from patients with advanced prostate cancer (PC), urothelial carcinoma (UC), and renal cell carcinoma (RCC). Plasma ctDNA and tissue genomic DNA were analyzed using NGS-based cell-free DNA assay, a modified version of FoundationOne Liquid (F1L) including blood tumor mutational burden (TMB) analysis, and tissue-based panel, FoundationOne CDx (F1CDx), respectively. Success rate of ctDNA was defined as the percentage of patients whose sample quality control status was “pass” or “qualified”. Level of ctDNA was defined as the maximum allele fraction (AF) for all known somatic alterations detected. Results: As of June 18, 2020, ctDNA analysis results were available for 470 of 540 patients with advanced solid tumors. Among them, we analyzed 70 advanced GU cancers (35 PC, 17 UC, and 18 RCC) and 400 non-GU cancers. The success rate of ctDNA was significantly lower in GU cancers than in non-GU cancers (81.4% vs. 91.5%, P = 0.016). The levels of ctDNA in PC and UC were similar to those in non-GU cancers. RCC had the second lowest ctDNA level (median 0.13%) after that in malignant melanoma. The median TMB, as estimated by ctDNA, was 4.40, 0.88 and 0.44 mutations/Mb in UC, PC and RCC, respectively. The most frequently altered genes were TP53 (34%), AR (11%), BRCA2 (11%), ATM (8.6%), and CDK12 (8.6%) in PC, TP53 (59%), TERT (41%), and CHEK2 (18%) in UC, and TP53 (22%), ATM (11%), and MTOR (11%) in RCC. The mutation rate in genes related to DNA damage response (DDR) pathways was significantly higher in GU cancers compared to that in non-GU cancers (30.0% vs. 18.0%, P = 0.033). However, other pathways were less frequently altered in GU cancers versus non-GU cancers, including Wnt (5.7% vs. 16.8%, P = 0.017), PI3K (8.6% vs. 19.0%, P = 0.039) and RAS/MAPK (8.6% vs. 29.5%, P < 0.001). Conclusions: Our results reveal the genomic landscape of ctDNA in several advanced solid tumors, and highlight the differences between tumor types. Comprehensive analysis of ctDNA using the F1L assay reveled alterations in DDR-associated genes were significantly more frequent in GU cancers than in non-GU cancers. Clinical trial information: UMIN000036749.