Therapeutic enzymes have important roles in cancer treatment. Thus, our research target was to isolate fungi from Saudi soil; so examined their ability to produce L-arginase and identified them by 18S rRNA. From among the 20 fungal isolates recovered from the rhizosphere in the north and south of the city of Jeddah Province in Saudi Arabia, eight isolates produced high quantities of L-arginase. Highly produced fungal isolates were identified in the 18S rRNA sequence using DNA sequences of ITS1 and ITS4 and deposited in GenBank under joint numbers such as Aspergillus oryzaeXR_002735719.1, Penicillium oxalicum MH156644.1, Penicillium oxalicum MH171483.1, Aspergillus niger MF093522.1, Rhizopus oryzae AB250174.1, Aspergillus fumigates KJ746594.1, Fusarium equiseti KY945342.1, and Rhizopus oryzae AB250174. The highest producer of the enzyme was Fusarium equisetiKY945342.1 (2.492IU/mg & 1.952 IU/mg by Penicillium oxalicum MH156644.1).