Determining the associated Dipteran flies in Volvariella volvacea mushroom cultivation is important since these flies are purportedly potential pests of mushrooms especially in their immature stages. To address this, mushroom bed establishment and adult fly sampling at different growth stages of V. volvacea mushrooms by net-sweeping and use of sticky boards were done at weekly intervals. Net-sweeping revealed catches of adult flies which were identified using appropriate taxonomic keys; however, insects collected by sticky boards were mutilated and identification was not possible. Eight species of flies found exhibited the breadth of dipteran diversity; three families represented the suborder Nematocera (Scatopsidae, Sciaridae, and Empididae) and five of the suborder Brachycera namely, Mycophila (Cecidomyiidae), Pipunculus (Pipunculidae), Porcenus (Heleomyzidae), Leptocera (Sphaeroceridae), and Desmometopa (Milichiidae). The most abundant fly was Desmometopa in the eight weekly samplings signifying that the mushroom substrate was supporting this fly population. Desmometopa, as well as Porcenus and Scatopsidae flies are known detritivores, while Sciaridae and Cecidomyiidae represented by Mycophila are known fungivores. Pipunculus and the Empididae fly are endoparasite and predator, respectively.