The objective of the study was to explore the incidence of patulin (PAT) mycotoxin in mango and orange fruits and derived products marketed in Pakistan. A total of 274 samples, including 70 mango fruits, 63 mango-based products (juices, pulp, and jam), 77 orange fruits, and 64 orange-based products, were collected. PAT was determined by reverse-phase high-performance liquid chromatography (HPLC) with UV-Vis detector (276 nm). Linear detector response was observed (R2 > 0.99), the limit of detection (LOD) was 5 µg/kg and recovery percentage was 97.4%. The incidence of PAT in mango samples was 61.7%, and the concentration ranged from <LOD to 6415 µg/kg with a mean of 110.9 µg/kg. Our results showed the high susceptibility of mango fruits to patulin, and it was observed that decayed mango fruits were most contaminated with PAT. Among the mango samples, PAT concentration was higher in fruits than in processed products such as mango juice, pulp, and jam. Toxin incidence in orange samples was 52.5% with concentrations from <LOD to 61 µg/kg and a mean of 6.3 µg/kg. As much as 29 samples of mango (21.8%) contained PAT concentration above the regulatory limit (50 µg/kg), whereas there was only one exceeding orange sample (0.7%). Our results show that PAT seems to be a problem in fruits, juices, and derived solid products, especially from mango, and needs surveillance on regular basis.