Biotransformation of Diclofenac was performed by Scytalidium thermophilum isolated from sheep dung at pH 6.0, a temperature of 45±°C, in 4 day incubation period. By morphological features and 28S rDNA sequencing, the strain was identified as Scytalidium thermophilum. The metabolites were confirmed by HPLC analysis of the extract of experimental flasks. The transformation of Diclofenac was identified by LC-MS. The results prove that thermophilic coprophilic fungus S. thermophilum is a promising fungus for diclofenac biotransformation. Hence, this fungus can be explored for the synthesis of biotransformation products.