In patients with advanced cancer, it is necessary to detect driver mutations and genetic arrangements. If a mutation is found, targeted therapy may become an option. However, in most patients with advanced cancer, obtaining material can be challenging, and these determinations must be made based on small biopsies or cytologic samples. We analyzed the ability of liquid-based cytology to determine the mutational status in patients with advanced cancer by next-generation sequencing. We studied cytologic samples from 28 patients between 1 January 2018 and 31 December 2022. All samples were processed by next-generation sequencing using the Oncomine®Precision and Comprehensive Assay Panels for Solid Tumors. Eleven male and 17 female patients with a median age of 63.75 years were included. Clinical stage IV was predominant in 21 patients. Eleven patients died, and 17 survived. The DNA and RNA concentrations were 10.53 ng/µL and 13 ng/µL, respectively. Eleven patients showed actionable mutations, and 17 showed other genomic alterations. Liquid-based cytology can be used as a component of liquid biopsy, as it allows the identification of actionable mutations in patients with advanced oncological disease. Our findings expand the utility of liquid biopsy from different body fluids or cell aspirates.