William Sidney Porter, better known to millions under his pen name, O.Henry is the most popular short story writer in American literary history. Some people have called him the twentieth century Balzac. Some have called him the American Maupassant because of his so well made surprising endings. The short story is the fundamental and self contained genre in American prose fiction, and the stories of O.Henry certainly made their appearance in consequence of the prolonged and incessant cultivation of the genre. The real O.Henry is found in an irony pervading all his stories, in a keen feeling for form and traditions. Americans cannot help wanting to prove a resemblance in outlook between him and Shakespeare – it is their way of expressing “national pride”. The present study is aimed at bringing out thematic concerns in the short stories of O.Henry. This work is a modest attempt to execute the predominant themes and techniques in the short stories of O.Henry and conducting a literary research into the multitudinous perspective of O.Henry’s genius permeating through his short stories along side a projection of his varied thoughts as a versatile fictionist and professional journalist.