The Mandaic language has been used since Late Antiquity by the Mandaean community of Iraq and Iran as a spoken and literary idiom. The presently available Mandaic Dictionary, published in 1963, is a valuable reference tool that greatly advanced research into this much neglected Eastern Aramaic dialect. However, as the article seeks to highlight, both in terms of the scope of its corpus and its analysis, it does not conform to the current needs and achievements of Aramaic lexicography, and is in need of replacement. The first of two studies, the article discusses the dictionary's analysis and presentation of the linguistic data that was available to the authors at the time of its publication, indicates its weaknesses in various areas, and proposes criteria for better lexicographical analysis of the source material.