A lipomais benign soft tissue tumour of adipose tissue which is mostly covered with a sheath of fibrous capsule and found mostly in subcutaneous tissue plane. A lipoma can be found anywhere where fat is located in the body. Rarely, they can occur deep to subcutaneous tissue and very rarely deep to submuscular plane. Deep submuscularlipomas are large by the time they present clinically and are liable to cause compression of neurovascular structure in the vicinity. In proximal forearm, they can compress theradial nervewhere it divides into posterior interosseous nerve (PIN) and superficial radial nerve which may result in weakness of extensor group of muscles of fingers and sensory loss over the dorsoradial aspect of hand. I am presenting a case of large submuscularlipoma, in a 44 years old female, deep to supinator muscle compressing the radial nerve at its division into PIN and superficial radial nerve.