The paper is conceptually divided into four parts. In the first part the widely held view that ancient Hinduism was not a missionary religion is presented. (The term ancient is employed to characterize the period in the history of Hinduism extending from fifth century B.C.E. to the tenth century. The term 'missionary religion' is used to designate a religion which places its followers under an obligation to missionize.) In the second part the conception of conversion in the context of ancient Hinduism is clarified and it is explained how this conception differs from the notion of conversion as found in Christianity. In the third part the view that ancient Hinduism was not a missionary religion is challenged by presenting textual evidence that ancient Hinduism was in fact a missionary religion, inasmuch as it placed a well-defined segment of its members under an obligation to undertake missionary activity. Such historical material as serves to confirm the textual evidence is then presented in the fourth part. The paper is conceptually divided into four parts. In the first part the widely held view that ancient Hinduism was not a missionary religion is presented. (The term ancient is employed to characterize the period in the history of Hinduism extending from fifth century B.C.E. to the tenth century. The term 'missionary religion' is used to designate a religion which places its followers under an obligation to missionize.) In the second part the conception of conversion in the context of ancient Hinduism is clarified and it is explained how this conception differs from the notion of conversion as found in Christianity. In the third part the view that ancient Hinduism was not a missionary religion is challenged by presenting textual evidence that ancient Hinduism was in fact a missionary religion, inasmuch as it placed a well-defined segment of its members under an obligation to undertake missionary activity. Such historical material as serves to confirm the textual evidence is then presented in the fourth part.