Sliced fruits are widely consumed for their nutritional benefits; however, improper handling can lead to microbial contamination, posing public health risks. Serratia marcescens is an opportunistic pathogen capable of transmission through contaminated food. This research focused on detecting the presence of Serratia marcescens in sliced fruits sold in the Yakuba area of Ilorin. A total of 50 samples comprising watermelon (36%), pawpaw (34%), and pineapple (30%) were collected from six vendors. Isolation and identification of Serratia marcescens were performed using standard microbiological techniques. Antibiotic susceptibility testing was also conducted using the Kirby-Bauer disc diffusion method. Two isolates were identified as Serratia marcescens, accounting for 4% of all samples; both were found in watermelon, giving a fruit specific prevalence of 11.11% (2/18). No contamination was detected in pawpaw or pineapple samples. The contaminated samples originated exclusively from Vendor 3, resulting in a vendor-specific contamination rate of 22.22%. Antibiotic susceptibility testing showed that the isolates were 100% susceptible to ceftriaxone, trimethoprim-sulfamethoxazole, gentamicin, and tetracycline but showed complete resistance to ampicillin. In conclusion, the sliced fruit samples were contaminated with Serratia marcescens, and the isolates were resistant to one of the commonly used antibiotics.